BJ Deming

Monitoring Popocatépetl

We sometimes worship volcanoes. We always fear them. We also love them, a little — but only in the last hundred and fifty years has H. sapiens developed effective ways to manage the crises that volcanoes literally throw at us.

These methods include:

It isn’t easy for experts to communicate their specialized understanding of the big picture to laypeople who are in harm’s way but see things from a completely different perspective.

To complicate matters, there also is at least some scientific uncertainty about a volcano’s state at any given moment because of the inherent difficulties of studying processes that start miles underground and then escalate into conditions at the surface that no observer can survive.

Earth is so big that we’re all more or less like the fabled blind men trying to describe an elephant.

But life under the volcano has its urgencies, so experts do the best they can to get the word out, and they always try to say it better and more clearly each time the volcano rumbles.

The people — who usually don’t have much technical background but who also lack reliable alternatives when the local mountain starts to shake and glow — try their best to understand and act on information that sometimes sounds like nonsense to them.

With luck and a little experience, it can work out.

The routines of life are broadened, not destroyed, by what is actually common sense (“The volcano can kill you in so many ways if you go into that exclusion zone” or “Your town sits at the mouth of a ravine that can funnel fiery death clouds down onto you, so there are shelters set up for you in a safer area until this eruption is over”).

Sometimes they’re even strengthened as mutual trust forms between laypeople and scientists in a long-term emergency, with the years passing and good decisions, forged early on in fire and fear, proving their worth.

Then everyone under the volcano is safer and less anxious because now there is a plan.

That’s the goal, anyway. Real life is messier.

Here’s how things went when tens of millions of personal perspectives, along with some of the best minds on the planet, were thrown into crisis as Mexico’s Popocatépetl woke up and began erupting in late 1994, after many decades of quiet.

I normally wouldn’t know what that was like for people near the volcano, but ClioTV, a documentary maker in Mexico, presented their side in a 2002 presentation, El volcán que escucha (“The volcano that listens”), which ClioTV recently uploaded to YouTube.

That human story is compelling in its own right, but it is also worth sharing here in the form of interview and narration excerpts because it highlights with amazing clarity the sorts of challenges encountered worldwide outside the halls of Academia and officialdom when a volcano threatens people and their stuff.

I have filled in the science side of the story from references listed at the end of this post.

Popocatépetl is still erupting in 2025, but life now goes on fairly smoothly under this volcano.

Climbing the volcano and living with it

Modern volcanology was too new to study Popocatépetl in depth during its 1920s eruption, which was relatively short and fairly quiet.

The volcano eventually dozed off, except for steaming fumaroles and a few light snores in 1933, 1943, and 1947.

This famous 18,000-foot-tall ice-capped sentinel above the Paso de Cortes, between Mexico City and the city/state of Puebla, was now safe to climb and many did so although the ascent is not easy, as this 1992 video (Spanish) shows.

That’s 74 minutes of vintage shaky cam, but even if you’re not into mountaineering or geology, near the beginning of it are some features that we’ll return to later in this post:

  • The steaming crater. That white steam cloud is seen at the start:

    They reach the 2,000 x 2,600-foot-wide hole in Popocatépetl’s summit — it was about a thousand feet deep back then and contained a small seasonal crater lake — at the fifty-minute mark.

    Steam was a sign that Popocatépetl was waking up, something scientists had suspected ever since January 1986, when climbers first reported seeing more fumaroles in the summit crater than usual.

  • Glaciers, which can melt very quickly during an eruption and cause destructive mudflows called lahars.

    In 1985, a lahar at icy Nevado del Ruiz volcano killed more than 25,000 of the 30,000 residents of Armero, Colombia. Awareness of that tragedy would influence evacuation decisions made nine years later when Popocatépetl awoke.

  • The fact that it’s 1992, the last relatively quiet year on the mountain.

    Popocatépetl would become much more restive in the months leading up to its eruption in late December 1994.

    Volcanologists could compare those significant changes with earlier data that they had collected in person at the summit during at least fifteen science-related ascents in 1992, along with records from the geodetic monitoring networks that they set up on the north flank in February of that year. (GVP)

But not everyone on and around Popocatépetl is a mountaineer or a scientist.

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…the little volcanoes are alive we as people say that they are Peñas are hills but imagine us we did not plant them only our father who is in heaven are the ones who planted them because you do not want until… We are his and why are we not going to believe in that because very ignorant people never believe that volcanoes are alive Well yes of course they have to be alive for that reason Anyway but only God knows in what way we know that you are the only God that all…things the volcano has this…spirit that inhabits it a spirit that inhabits its interior…”

— Doña Inés Campos, Santiago Xalitzintla (ClioTV, 00:06:24, Google Translate)

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The ClioTV documentary El Volcán Que Escucha (“The Volcano That Listens”) gives voice to some of the rural and indigenous people on Popocatépetl — the town of Santiago Xalitzintla, for example, is less than eight miles from the volcano’s summit.

There are tens of thousands of them up there, farming, marketing, just getting by somehow, in more than twenty small villages and towns.

Many don’t need science or cameras to see the volcano that has been their ancestral home for thousands of years. Intuition satisfies their very human need for connection and a sense of control over the situation.

Why not?

Volcanoes are fascinating, and like the Earth, they are big enough for people of all backgrounds to want to talk about as best they can, much as those blind men tried to describe the amazing phenomenon that is an elephant.

For experts who study Popocatépetl, the best way to do this is through Science. For some laypeople who live on Popocatépetl, their best words come from Religion.

Science cannot prove a negative, that there is no god at this volcano. Believers cannot say that their omniscient, omnipresent deity doesn’t also exist in and operate through science.

It’s a draw, basically, but human nature being what it is, sides are often taken and scorn is heaped upon “the other.”

Perhaps the words of Doña Inés — “…very ignorant people never believe that volcanoes are alive” — reflect other words she has heard, from “the other,” expressing as fact the prejudice that animism is primitive superstition.

Human complications like this make things even tougher when a volcano — which is above such matters — wakes up.

In such a setting, how would you communicate volcanic risk to those who revere Popocatépetl (Spanish), who sometimes see it as an old man whom they call Don Gregorio Chino Popocatépetl or Don Goyo?

Six hundred years earlier, the fire mountain was Xalliquehuac, “flying ash,” to its Aztec neighbors.

And, 1,400 years before that, Mesoamericans living on the volcano’s eastern flank at a site known today as Tetimpa were capping the volcano shrines in their courtyards with a ceramic human face, cheeks puffed out and mouth open as if blowing. (Plunkett and Urunuela)

What names they gave to this face and to the volcano were not preserved by the layer of yellow pumice, 3 to 5 feet thick, that buried Tetimpa’s prehistoric village and its shrines (but not its people) “Pompeii”-like in the first century BC.

Unfortunately, Volcán Popocatépetl does not always have the sort of relatively quiet eruptions that have been its style since humans first started to record them in the 1300s AD.

Though the events are beyond living memory now, sometimes Popocatépetl gets violent.

Hazards at Popocatépetl

As volcanology developed over the twentieth century, dormant Popocatépetl, located near the seat of national government and surrounded by tens of millions of people, became a research magnet.

Before 1994, Mexican and international scientists could not practice their new science to study its eruptions in real time. Instead, they carefully examined the debris left by past eruptions.

This included exposed lava and pyroclastic formations on Popocatépetl’s summit and flanks (some of which are seen in the 1992 video that was linked earlier).

The boffins also searched lowlands for traces of ashfall, lava, mudflow deposits, and anything else that the volcano might have ejected during its roughly 23,000-year history.

How could knowledge of the past help them understand a sleeping volcano in the here and now?

Studies around the world have shown that geologic evidence of what a fire mountain has done in the past gives volcanologists very useful clues about what it’s most likely to do again, this time as a part of human history. (De La Cruz-Reyna and Tilling)

Since Popocatépetl remained visibly quiet in the late 1980s and early 1990s, the public wasn’t interested in such arcane investigations, but in academic circles the study results surprised everyone.

Besides finding traces of multiple rounds of low-level VEI 1 and VEI 2 activity that probably was similar to the eruption that’s still going on at the time of writing, volcanologists also discovered that Popocatépetl has had plinian eruptions — VEI 4 to VEI 5 or more. The marks of these violent events are all too clearly recorded in the rocky outcrops found in villages, small towns, and cities around the volcano. (Siebe and Macias).

These “big ones” occur at intervals of 1,000 to 3,000 years, according to Siebe and Macias, who have counted at least four of them at Popocatépetl since the last ice age ended.

The last one, they note, happened about 1,200 years ago and destroyed or had major impacts on surrounding Mesoamerican settlements, even though these lacked the energy grids, water and sewer lines, and transportation networks (ground and air) for 27 million people that would be crippled or shut down by a plinian eruption here today.

In addition, heavy rains and/or glacial melt washed tons of ash from each of Popocatépetl’s “big ones” down the mountainous region’s slopes, causing huge lahars into the basins of Mexico and Puebla.

Mesoamerican pottery fragments embedded in these thick mudflows are the only sign today of communities that were lost to such disasters.

In Pleistocene times, lahars buried mammoths.

Now, both geographic basins are home to about forty percent of Mexico’s population, its national government, most of the country’s industry, and the production of more than thirty percent of its gross national product. (Siebe and Macias; Wikipedia)

Ready for more bad news?

Starting in 1987 (Siebe and Macias), experts began to realize that this stratovolcano — known affectionately as “the Colossus of Puebla” — is only the most recent of a whole family of cones.

At least two other volcanoes have stood here, one after the other in the distant past, and then the volcano collapsed.

Many earth scientists consider Ventorrillo — the rocky area where that 1992 ascent video begins — to be a collapse scar of the last volcano before Popocatépetl. (Siebe and Macias)

Ventorrillo is the concave flank structure to the right in this image of gigantic Popocatépetl by Julio César García from Pixabay (public domain)

These were not small events.

When each ancient volcano fell down, an enormous landslide, technically, a debris avalanche, sped at least 45 miles southward into what is now Morelos State (population almost two million in 2020).

The suddenly uncapped hydrothermal system went up in a massive blast that was followed by a plinian eruption.

And today’s Popocatépetl is about as tall as stratovolcanoes typically get. (Siebe and Macias)

  • Violent eruptions
  • Lahars
  • Mount St. Helens style landslides and blasts

Something akin to existential dread motivated those fifteen research expeditions up to Popocatépetl’s summit in 1992!

At first, few outside Academia’s ivory walls were even aware that there were concerns (De La Cruz-Reyna et al.) — not that most laypeople, including emergency management authorities, had they been told of it, would have known enough geology to easily understand that problem and its implications.

Then, in 1993, the situation escalated.

Monitoring, 1986 to December 21, 1994

I wasn’t there. My sources for this and the next section, unless otherwise noted, are the Smithsonian’s Global Volcanism Program (GVP) website, Martin-Del Pozzo, and De La Cruz-Reyna and Tilling.

After mountaineers first reported seeing increased summit fumaroles in 1986, with some of the steam vents glowing (a feature that hadn’t been noted before), engineers at the University of Mexico (UNAM) established a seismic station at Altzomoni, seven and a half miles north of the summit as part of the Valley of Mexico seismic network.

That was in 1987. It didn’t pick up low-level activity very well, so two years later UNAM’s geophysicists set up the first telemetered seismic station actually on the volcano at Tlamacas.

Located on the north flank at an elevation of a little over 13,000 feet, Tlamacas is the highest point on Popocatépetl that can be reached by car (Siebe and Macias) and I suspect that it is the building complex shown at the end of that 1992 climbing video.

Seismic precursors to an eruption probably first showed up on these instruments in 1990, according to De La Cruz-Reyna and Tilling.

Those initial signals were very subtle, as were changes demonstrated by other methods, such as the monitoring of spring water chemistry on the volcano that began in 1988.

Since scientists had no baseline — no earlier data to compare this new information to — eruption precursors could not be recognized except in hindsight.

1988 also saw the establishment, with technical and financial support from Japan, of the National Center for Disaster Prevention (CENAPRED). Part of its mission is to monitor Mexico’s volcanoes, and it has an ad-hoc scientific committee dedicated to Popocatépetl. (De La Cruz-Reyna et al.)

In 1989, Boudal and Robin published a paper that summarized findings to date and included maps of various hazards and lists of towns and other areas likely to be affected by each hazard.

A risk assessment based on this paper would guide the first round of evacuations in December 1994.

Throughout this time, the activities of those people living on Popocatépetl are not recorded in the sources I’ve followed.

Presumably they continued their subsistence farming and/or other daily activities, while the faithful among them probably went up to a holy place near the volcano’s summit each year on March 12 to celebrate Don Goyo’s birthday. (ClioTV)

In February 1992, as mentioned, a geodetic network was set up on Popocatépetl’s north flank.

The volcano stopped being subtle in 1993. A series of plumes, visible from Puebla, went up from its summit, starting in January.

During the year, at least thirty new fumaroles opened up on the summit crater floor, and by November, Popocatépetl was sporting a 30-mile-long steam cloud.

There was still no uptick in seismicity.

In its place, especially during the first half of 1994, plenty of human shaking, so to speak, was going on.

Many untrained but curious observers climbed up for a look and brought back reports of “molten lava” and “phreatic eruptions.” The Global Volcanism Program attributed these at the time to the new fumaroles, which were powerful, deposited molten sulfur, and did sometimes have a red glow.

The crater lake warmed and changed color, but GVP experts wrote in February 1994 that “…with no previous [eruption] records from Popocatépetl, one must be careful about reaching conclusions before a good baseline is available.”

That may sound too cautious to us, knowing as we do in 2025 that the volcano would erupt, but experts couldn’t be sure of that through most of 1994.

They did know that local residents, rural and urban, were excited and worried — few had personally experienced the last eruption. Also, an airline pilot had reported seeing an ash cloud, which caused a stir in Mexico City’s air traffic control although no ash was found when scientists looked (they decided that he had mistaken the fumarolic plume for ash).

With public anxiety high, if the volcanologists spoke too soon and then the rising magma stalled — it does happen — their credibility would plummet and people might ignore the next warning and get blindsided by an eruption. (Oprea)

Even today, geoscientists do not know exactly what tips a restless volcano over into the stage where eruption becomes inevitable.

Back in 1994, uncertainty based on the new knowledge of Popocatépetl’s sometimes vicious history was a factor, too.

As Roberto Quass, former CENAPRED director, remembered it for ClioTV in 2002 (via Google Translate, 00:02:45):

“We knew that sooner or later the volcano was going to reactivate. But we didn’t know how it was going to happen. Many people thought that the reactivation of the volcano was going to be of great magnitude, one of these large eruptions that destroy everything in their path for miles around. On the other hand, many others thought that the activity was very similar to the one of the [19]20s.”

Disagreement is part of the science process, but it can be very hard on laypeople who need expert advice about something so serious and with such high stakes.

In 1994, UNAM added a department dedicated to Popocatépetl. (Oprea)

In May of that year sulfur dioxide readings at Popocatépetl began to rise as magma approached the surface, and in October seismicity suddenly increased two- to tenfold.

Now federal and state authorities formed an Emergency Committee composed of scientists from UNAM and other universities, as well as a team from CENAPRED. (This evolved into an advisory science committee on Popocatépetl that has been around, in one form or another, ever since.)

Phone and fax consults were obtained with volcanologists in the US Geological Survey who had recent experience with reawakening explosive volcanoes at Mount St. Helens in Washington State and at Mount Pinatubo in the Philippines.

The Emergency Committee produced a risk assessment from Boudal and Robin’s 1989 study, and two more seismic stations were set up on Popocatépetl’s southern flanks in October and November 1994.

Then, shortly before 2 a.m., local time, on December 21, 1994, after a quick series of seismic jolts, the volcano’s summit crater exploded.

What would come next?

Soon a little ash was falling on several towns to the east and also on Puebla City, almost thirty miles away.

While scientists had gathered a trove of data over the last eight years, they could not yet put it all together in ways that would quickly address this emergency.

The underlying problem was that Popocatépetl had never erupted during the era of modern instrumentation.

Volcanologists knew what they were seeing on the instruments and out the window, but not what it meant in terms of the eruption’s likely development.

The beginnings of such active processes early in an eruption leave few traces in the geologic record.

Yes, Popocatépetl was erupting, but:

  • Did its eruptions always start so violently?
  • More than a thousand years had passed since the last “big one.” Was Popocatépetl about to go plinian?
  • With all those steaming fumaroles over the last eight years, was the cone stable?

More than 20 million people watched their local volcano rage on through the long hours before dawn, while phone calls and other messages summoned back all the scientists and public officials who had already left for the holidays.

December 22, 1994 to January 2001

At such times, a detailed written plan provides valuable guidance, but in December 1994 no emergency plan existed.

However, there was the Committee’s risk assessment from Boudal and Robin’s 1989 hazards paper.

No formal alert system was in place yet to inform the public and to guide official decisionmaking and emergency actions, but information gathered over the past eight years did give experts a better knowledge of Popocatépetl than had ever been possible before.

But here my own narrative must break into a couple of subsections — I see two different versions of the early emergency response to Popocatépetl’s 1994 eruption, one that comes from the scientific reports that I’ve read and one that I’ve seen in the ClioTV documentary introducing us to residents in settlements on the volcano.

Taken together, these two views, instead of matching up, show the real-life messiness that can happen when a volcano wakes up and its human neighbors are not thoroughly prepared for it.

Thirty-one years after Popocatépetl first went off, this unpreparedness still exists at many, though not all, volcanoes world-wide.

Science — A Plan and…a Traffic Light?

When daylight came on December 22, 1994, incredibly, people were on the mountain, according to the Global Volcanism Program:

Claus Siebe reported that climbers at Popocatépetl reached the summit, which lies along the W margin of the gaping summit crater’s rim, both on the day before the eruption, and hours after the 21 December eruption started…

Curiously, the six volcanic earthquakes that took place between 0130 and 0200 on 21 December were not felt, and the presumably associated phreatic [magma + water] summit explosions were not heard by any of about 25 mountain climbers at Tlamacas, 4 km N of the summit (figure 6). The climbers, who said they started ascending the mountain around 0400 on 21 December, did not notice anything unusual until they neared the crater rim. Just prior to reaching the rim, a few minutes before 0800, climbers were stunned by what they thought was the sound of jet engines. At the crater rim they saw new bombs [large chunks of tephra] as large as 40 cm that had been thrown out of the 250-m-deep crater and had burrowed deep impact-pits in the snow. According to Siebe: “Most climbers who reached the summit that morning thought that the activity was normal, because they had never visited Popocatépetl before.” At the summit, the climbers said they could not see the crater floor even though a strong wind was blowing. They descended back down the mountain without incident.
Siebe was at Tlamacas at 0900 on 21 December during clear weather. He observed a continuous ash plume rising 100-500 m above the crater with pulses at intervals of 1-5 minutes. The plume was carried at least 60 km E. Enough silt- and sand-sized material reached Puebla to produce a thin coating on cars…

The ash plume grew in size later in the day.

Multiple consults about what to do took place on the 22nd between Civil Protection personnel and the Emergency Committee.

Cracks had visibly widened on the summit glaciers, and the memory of that 1985 lahar tragedy at Armero, Colombia, was on everyone’s mind. (De La Cruz-Reyna et al.).

An evacuation was called in vulnerable areas close to the volcano, based on the Committee’s risk assessment. (See the next section for how that went from the evacuee perspective.)

Also, Mexican and US geoscientists began to collaborate on a new Popocatépetl hazard map — the first one intended for use by civil authorities.

It would be ready in a few months (which is very quick work for such a project).

Popocatépetl grew quieter on Christmas Eve, which was a nice gift for volcanologists who knew that each of the volcano’s plinian eruptions had started with minor ashfall and then somehow escalated. (Siebe and Macias)

That apparently wasn’t going to happen now — at least, not right away. (As it turned out, this initial eruption in 1994 was explosive thanks to the interactions between rising magma and ground water; after clearing its throat this way, Popocatépetl went into mostly VEI 1 to 2 lava dome-building eruptions that have continued from 1996 on through today.)

Glacier monitoring continued, but Popocatépetl exhibited only intermittent low-level “exhalations” of ash, steam, and volcanic gases throughout 1995 and into 1996.

As time passed, although a summit exclusion zone was still in effect, the fire mountain was visibly calmer and occasionally people would climb up to the crater’s edge.

Five of them died in 1996 when Popocatépetl’s first lava dome exploded. (Always respect the exclusion zone, please, and the volcanic power such zones are meant to protect us from!)

As hazard mapping and associated emergency actions went on in late 1994 and in 1995, other Committee members grappled with the question of how to communicate volcanic risk to some 25 million people.

These experts reviewed volcano alert systems in various parts of the world to get ideas for a code that might work at Popocatépetl.

There is no international standard for such things, apart from the Aviation Color Code used to warn aircraft about drifting volcanic ash clouds (which can damage or even shut down engines).

Alert systems are usually based on what the volcano is doing. Levels can be expressed as colors or numbers, with “1” being either the lowest or highest alert.

A typical color sequence is Green for “normal” up through Yellow and Orange to Red (“erupting, evacuate at once”).

It was hard to find a good fit for Popocatépetl since most systems were not designed for such a large population with such a wide range of backgrounds — from the PhD’s at UNAM, to tourists, shopkeepers, journalists, workers, and national government authorities in Mexico City, to the rural indigenous people in hard-scrapple settlements on the volcano’s slopes.

How to get these tens of millions of very different people all on the same page, in terms of volcano risk awareness? (De La Cruz-Reyna et al.)

El Semaforo, the Traffic Light System

Input on various alert system proposals from a variety of sources, including non-governmental organizations and individuals, showed volcanologists that the intermediate alert stages required when Popocatépetl is neither dormant (Green) nor violently exploding (Red) confused the general public. (De La Cruz-Reyna et al.)

What finally emerged in mid-1995 from all these discussions was something a little unusual but with a very familiar appearance.

CENAPRED

The approach here is twofold. Instead of linking volcanic activity to alert level, Popocatépetl’s Volcano Traffic Light Alert System (VTLAS) focuses on public safety awareness (the traffic light color) AND phases that trigger predefined Civil Protection measures.

Colors are for the public and are kept simple to reduce ambiguity (De La Cruz-Reyna et al.):

  • Green: Everything is fine.
  • Yellow: Be aware of risk and watch the volcano.
  • Red: Leave the area.

That’s all there is to it, and the traffic light has been Yellow, with a couple of exceptions, ever since it was established in 1995, even when the volcano appeared to be quiet.

Of course, that led to jokes about the “busted traffic light” stuck on Yellow, but gradually the idea sank in that El Semaforo is about people’s need to be aware, not about the volcano itself.

For emergency managers, each color has phases — two for Green, three for Yellow, and two for Red, based on the Committee’s most likely scenarios.

These indicate which levels of emergency response are needed.

Red Phase 2 is for Popocatépetl’s “big one,” if such a cataclysm ever occurs in our time. Since 1994, though, the Traffic Light has usually been set at Yellow Phase 2 or 3.

Of course there were glitches when El Semaforo first took effect, most notably in 1997.

That’s when Popocatépetl’s increased explosiveness raised a tall plume and ash fell in Mexico City for the first of at least nineteen such dustings thus far.

In response, the traffic light went to Red, Phase 1, which calls for evacuation.

The science committee did suggest another round of evacuations, but civil officials refused for reasons that weren’t mentioned in the papers that I’ve read.

This mixed message upset the public, and experts had to redefine some of the phases.

Today, the Popocatépetl traffic light is routine news, just like the weather forecast.

However, that’s only because public trust in this system has grown over the years after a very rocky start.

ClioTV: 1994 and 2000 evacuation experiences

El Volcán Que Escucha has some excellent shots of the 1994 eruption’s early stage, including a brief view of Popocatépetl’s summit glacier glistening in sunlight after a strong east wind had scoured off the snow.

It’s worth watching even if you don’t speak Spanish — I don’t, but YouTube has an autotranslation option, and transcripts can be translated (as in this subsection, via Google Translate).

We also see evidence of Mexico’s authoritarian tradition, with armed soldiers conducting evacuations.

There also are images of frightened-looking villagers riding in trucks, trudging along the road with their families and possessions, or staring numbly at the camera in a crowded shelter.

This documentary has more detail about an evacuation in 2000, but they did interview Doña Inés Campos about her experience in 1994:

00:04:41 …later when my sister came to us and said, “Do you almost hear the radio and almost can’t you see the volcano?” I said, “Oh, well, the volcano is emitting its cloud,” but I thought it was a cloud. It’s emitting its cloud, she says, “Yes, cloud, yes, it’s fumarole,” they already announced it. The volcano began to erupt at 3 in the morning. I said, “Oh, well.”

“Oh well” also seems to have been the attitude of that band of climbers who ascended Popocatépetl on the first morning of its eruption!

The ClioTV documentary narration continues:

…a few hours later, thousands of people were evacuated from the communities settled on the slopes of Popocatépetl. Doña Inés and her family abandoned their home, their animals, their property… Soon they would share their helplessness with hundreds of farmers from Puebla that were evicted and taken to the shelters.

It was not an overall good experience for them, per ClioTV, but when Popocatépetl’s explosiveness declined around Christmas, many evacuees were allowed to go home.

Not the people from lahar-prone towns like Santiago Xalitzintla, though.

They had to stay in shelters almost two weeks, through the Christmas and New Year’s holidays, although no lahars did descend that far down during this initial period.

I don’t know whether the evacuees understood the risk — neither ClioTV nor the people interviewed for that program ever mention lahars.

The December 2000 evacuations

After getting down to the business, starting in 1996, of building lava domes and then blowing them up, Popocatépetl was at its usual level of activity during early and mid 2000.

Then things began to intensify in August.

By November 2000 this fire mountain was having earthquakes in the magnitude 2-3 range, as well as an unusually high number of lesser temblors.

It was scary for people around the volcano and a worrisome sign for experts that fresh magma was coming up.

Midstream changes like this do happen at volcanoes, and now, almost six years into the eruption, detailed plans and procedures were in place to deal with whatever Popocatépetl might be cooking up (hopefully, though, not a “big one”).

El Semaforo went to Yellow Phase 3, and the exclusion zone was widened from 7 to 10 km (the nearest settlements are about 12 km from the summit).

Sure enough an overflight of the summit revealed a new dome in the crater.

On December 2, the volcano gave off a low-intensity but 90-minute long “exhalation” and soon its seismic swarms increased even further.

It was going into overtime on this dome!

Very strong harmonic tremor occurred intermittently, probably at times when the summit lava dome grew at rates faster than typical for stratovolcanoes.

It soon filled most of the volcano’s huge crater. No longer would those walls hold in dome explosions or keep pyroclastic flows away from the summit glacier, which was still sizable at that point and therefore a lahar threat.

By mid-December 2000, Popocatépetl’s harmonic temor was powerful enough to damage instruments. The shaking could be felt by people seven to eight miles away.

00:12:13 …the ground moved made a rumble when the hills thundered It was heard well trembling by itself dilated was trembling was trembling like that was buzzing like like something like a car they already turned it on the machine is working like that It was heard…

— Julia Flores and Carmelo Carmona, town of Santa Cruz, to ClioTV

International media coverage was intense, this time around, as word spread that a Mexican volcano near one of the world’s largest cities was ramping up.

Volcanologists on the Popocatépetl Committee noticed that this new round of activity fit a pattern that had recently been described in a Japanese research study.

Based on that, and with the help of computer modeling, they made a forecast, saying that a strong eruption would soon occur after a brief period of quiet.

How strong? That was unclear, but with the summit crater almost completely filled in, any eruption could affect the glacier in a big way.

So, based on this forecast, the Traffic Light went to Red and the exclusion zone widened to 13 km, which meant evacuation of more than twenty villages.

Mexico’s president, Vicente Fox, called the evacuation on December 15, 2000. (GVP; Oprea)

Mayors of some settlements close to but not actually in the exclusion zone also announced evacuations, which led to some confusion and panic.

Santiago Xalitzintla was within this zone. According to Doña Inés and ClioTV:

…At around 10 p.m., we saw that the sirens were already there, they were screaming, yelling…

00:23:54 All the communities get out because the volcano is coming. Get the children out, please, leave and who knows where. The Civil Protection system, the Red Cross, and the 25th Military Zone have been carrying out evacuation efforts for more than 6 hours. Together with auxiliary units surrounding the Pocatepetl volcano. The towns suddenly filled with sirens from patrol cars and soldiers everywhere with loudspeakers. Calling on people to get out because the volcano was going to explode. Well, I tell you, my children, oh, we’re not going here.

00:24:33 We stayed, we locked ourselves in to see what God says about us. I don’t think anything will happen. It’s better if we lock ourselves in. Then it’s done. a logical chain. The children begin to cry. The mothers worry, and everyone wants to, uh, leave the town, since they were younger. My kids were younger…For now, if they got scared, they’re already crying. No, mom, let’s go. Yes, let’s go, mom, let’s go. And yes, we trust. So, in reality, they’re not doing it because they’re convinced they’re running any risk, but simply because of how impactful the mobilization is…

Julia Flores and Carmelo Carmano, Santa Cruz, around 00:13:41:

… it really hit us well well here that they come to pick us up and if nothing else it hurt us no no no we didn’t know if it was already that it was going to explode or we didn’t know What to do what he was going to do So we had to get away from him…yes no I wasn’t scared that’s why I told him here my husband are you going to leave does it scare you go I’m staying I’m staying for the animals…I’m [not] going to abandon them…

This is an issue with evacuees during volcano emergencies around the world, even when poverty is not a major concern, as it was for Julia and Carmelo.

Time and again, people refuse to evacuate or they return to care for livestock or to just keep an eye on their property.

When they do, sometimes they get caught by pyroclastic flows or lahars. It has happened on Montserrat, in Indonesia, and in Japan, among other places.

At Popocatépetl, pyroclastic flows and hot tephra did melt the glaciers, which were just about gone by 2003 as a result, but it never generated Armero-sized lahars.

Only a couple of small ones threatened towns close to the summit, including Xalitzintla where there was some damage to a building and an orchard in 1997.

And, as mentioned, I see no mention of lahars in ClioTV’s dicumentary.

Did those people even know why they were being told to leave in 2000?

Ramón Peña, former director of Plan Popo, tells ClioTV at around 00:27:00:

They weren’t forced, they were insisted on, they were blackmailed, if you want, they were lied to, but there were no rifle butts, but many people were scared, worried, but not so much about the volcano. What really worried them was the attitude of the military toward the people of Santa Cruz [concerns of racism against indigenous people].

Overall, about 41,000 people left the area, about half of them without being told to leave. Some 14,000 would stay in shelters for ten days, while friends or relatives accommodated the rest. (GVP)

Meanwhile, from a scientific viewpoint, the daring forecast came true.

Popocatépetl did quiet down briefly. Then, starting with an explosion on December 18 that encouraged the departure of those who had stayed despite the evacuation order, there was a two-day eruption with lava fountaining in the crater and debris ejected for 3 to 4 miles down its flanks.

News media broadcast these images live, and the volcanic crisis was heavily covered around the world — disproportionately so, in the view of some researchers today.

From the perspective of the evacuees and others interviewed by ClioTV, the 2000 evacuation was very problematical.

Anthropologist Alfredo Paulo Maya, 00:27:15:

They didn’t ask, they didn’t notify. Once they took the people out, many houses were looted, corn, beans, firewood were stolen. Turkeys, what they found there, an evangelical who lives on that side, everything, everything, they stole everything he had, everything in his house, they stole corn, they stole shovels, they stole … machete.

There is much bitterness expressed in the documentary.

Per ClioTV narration and, at the end, Aurelio Fernandez, Director of the University Center for Prevention of Regional Disasters:

00:33:12: “The population was kept in shelters against their will, more fearful of having abandoned their heritage than of a real eruption. And they were already told that in order to accommodate them, so that President Vicente Fox would come and make sure everything was well organized. So they asked them to get up and that they would let them go back to bed. But that wasn’t the case. Then Fox had just come in and told these scientists that they were going to be there. They were sensational. So they set up a sham between the government and CENAPRED. This self-praise, this applause, and they told the whole world. You see, it didn’t go well.

It doesn’t sound as though it went at all well for the people.

As for the scientists, CENAPRED’s Roberto Quass told ClioTV at around 00:34:21: “…[W]hen you’re in a position where you have to make decisions at the moment they occur, with all the psychological pressures you have, with many hours of sleep deprivation, and you have to make and respond to the President with a clear, concise, thoughtful, and well-founded response, I would like to see those who criticize what they would have done in those situations with that responsibility.”

In 2018, De La Reyna-Cruz and Tilling wrote of the December 18-19, 2000, eruption that:

…thousands of evacuees could watch the striking view of showers of hot debris falling on the volcano flanks from the safety of their shelters.

As evacuees Benito Perez and Doña Inés recalled for ClioTV, starting at around 00:25:30:

…Imagine a shelter, with water shortages, possibly food shortages…and I say, well, good for the soldiers because for us, they didn’t give us more than filthy, rolled cauliflowers. I tell you, I got sick, I got sick, my girls vomited, and we had diarrhea.

Everyone was eventually allowed to go home towards the end of December, after volcanologists had forecasted another eruption on or around December 23 that, this time, didn’t happen.

About a month later, in January 2001, the big dome exploded. Pyroclastic flows and lahars got into the ravines leading to Xalitzintla and other towns but did not reach those settlements.

The whole experience must have left many people wondering just what exactly was the point of the exercise they all had gone through, messy success though it was (as would have been clear if the mid-December eruption had been more intense and had caused damage but, because of evacuation, very few fatalities).

As far as I know, there is still no descriptive, let alone emergency management, approach that includes both neat scientific objectivity and the very subjective and tangled human experience of life under any volcano when it erupts.

Some papers I have read call for the inclusion of social scientists in emergency planning and response.

But the people — how much can they endure before trust, or at least willingness to go along with authorities, disappears completely? (Siebe and Macias)

From the broader perspective, how can the gap between Science and The Public be bridged most effectively and humanely?

I don’t have answers to these questions.

Somehow, though, lessons were learned and everybody moved on.

A better crisis experience in 2023

Perhaps ClioTV or some other agent will eventually document exactly how things changed for everyone between 2000 and 2023, when the volcano went on another rampage.

All I know is that, starting in January 2023, Popocatépetl’s eruptions became unusually intense, ashfall caused many school and airport closures, and the volcano looked and sounded downright scary at times.

Nevertheless, authorities kept the traffic light at Yellow and CENAPRED repeatedly explained in its daily updates that even such activity as this was covered by this setting.

In May 2023, as lengthy episodes of intense harmonic tremor occurred along with continuous ash emissions, the alert phase did rise from 2 to 3, and emergency managers did ready those shelters and evacuation routes, just in case.

Fortunately, evacuation wasn’t needed. Popocatépetl began to calm down as May turned into June, and later that year Phase 2 alert levels were reinstituted.

That calm but not overly reassuring management by authorities, plus the willingness to share information with the public, undoubtedly helped many people stay away from rumor mills and sensationalistic but false online sources.

These days, many people know about and use CENAPRED’s website and other official online sources to look up hazards that might affect them and to find evacuation routes for their area.

While a “digital divide” between urban and rural areas reportedly does exist, there is also a new generation in the settlements on Popocatépetl’s flanks — young and middle-aged adults who are more open to science-based information that they can access in a variety of ways. (Kornei)

The world changes and people go along with it however they can.

Or not. The faithful of Santiago Xalitzintla reportedly defy the 12-km exlusion zone and go up to have a birthday party with Don Goyo every March 12.

People are very adaptable, though. This year, San Nicolas de los Ranchos, another town just outside the exclusion zone, turned March 12 into a carnival: Don Goyo Fest.

After all, March 12 was a feast day for Saint Gregory when the missions held sway. Today a more secular world chooses to celebrate the volcano, instead.

And down through millennia to today, people have also worshiped that volcano.

It just happens, this intuitive fascination when close to something so powerful and dangerous. When combined with a healthy but not overweening dose of science, it can be very good for everyone involved.

Meanwhile, in the technical realm, scientists can celebrate how far they have come in monitoring Popocatépetl and raising public awareness of the volcanic risk here.

But, being scientists, they won’t celebrate very much — they know how much more work is needed, particularly in terms of those “big ones.”

After three decades of eruption — not an unusually long time for Popocatépetl’s low-level events — it does seem unlikely that the fire mountain will suddenly go plinian.

But that can’t be totally ruled out now, over a thousand years after the last big one.

And what about the next eruption, and the next, at this very active volcano? One day it will happen, and no amount of color coding and phase numbering will protect tens of millions of men, women, and children from the volcano’s wrath.

The people will have to help themselves, with some assistance from their leaders and various public service and military entities.

Today’s ongoing public interest in Popocatépetl is building a basis for the best possible outcomes on that future day of need.

People no longer consider it odd to have an erupting volcano in their midst, and they are so used to the Traffic Light that awareness of the hazard is now a habit rather than something requiring much thought.

Too, social media has covered this eruption so thoroughly that few will forget it when the Traffic Light finally returns to Green.

Everyone will be better prepared for it when the color again changes as a sign that trouble once again is stirring in the “mountain that smokes” (translation of the Nahuatl popocatépetl).

Featured image: Cristobal Garciaferro/Shutterstock

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