Mount St. Helens Isn’t Erupting


That’s resuspended ash from earlier eruptions.

Yes, volcanoes can still be hazardous decades after they erupt. Several weeks ago, the Alaska Volcano Observatory noted resuspended ash from an eruption up there 106 years ago!


VA ADVISORY
DTG: 20181014/1620Z

VAAC: WASHINGTON

VOLCANO: ST. HELENS 321050
PSN: N4611 W12210

AREA: US-WASHINGTON

SUMMIT ELEV: 8363 FT (2549 M)

ADVISORY NR: 2018/004

INFO SOURCE: GOES-EAST. GOES-WEST. RADIOSONDE.
NWP MODELS. VOLCANO WEB CAMERA. UA OBSERVATION.
NWS.

ERUPTION DETAILS: NO ERUPTION – RE-SUSPENDED VA

OBS VA DTG: 14/1612Z

OBS VA CLD: SFC/FL090 N4614 W12215 – N4614 W12208
– N4609 W12208 – N4610 W12216 – N4614 W12215 MOV
W 20-25KT

FCST VA CLD +6HR: 14/2200Z SFC/FL090 N4615 W12216
– N4613 W12208 – N4609 W12208 – N4610 W12216 –
N4615 W12216

FCST VA CLD +12HR: 15/0400Z NO RE-SUSPENDED VA EXP

FCST VA CLD +18HR: 15/1000Z NO RE-SUSPENDED VA EXP

RMK: RE-SUSPENDED VA CLD SEEN IN STLT AND
WEB CAM. NWP MODEL GUIDANCE INDICATES WINDS OUT
OF THE E AT 20-25 KTS. WINDS SHOULD LOWER IN THE
LATER FCST PERIOD. FCST THRU T+6 HRS.
…KIBLER


STHE0004


Update, October 15, 2018: No need for another VAAC advisory, apparently (perhaps because it doesn’t get up to flight level), but resuspended ash is apparent again today in the VolcanoCam:


Note the light ash cloud streaming off to the right.

That can’t be fun for the volcano’s human neighbors!


Update, October 21, 2018: Here’s the official word, passed along this past Friday:

CASCADES VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, October 19, 2018, 7:50 AM PDT (Friday, October 19, 2018, 14:50 UTC)

CASCADE RANGE VOLCANOES
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Activity Update: All volcanoes in the Cascade Range of Oregon and Washington are at normal background levels of activity. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State; and Mount Hood, Mount Jefferson, Three Sisters, Newberry, and Crater Lake in Oregon.

Recent Observations: Activity at Cascade Range volcanoes remained at background levels throughout the week. Earlier in the week, strong winds stirred up dust and ash from deposits on the north side of Mount St. Helens, prompting notices of volcanic ash plumes. There was no eruption. As winds die down and rain moves in next week, the lingering dusty haze will dissipate. As we move into winter, snow and moisture will hold these fine particles in place.

The U.S. Geological Survey and Pacific Northwest Seismic Network (PNSN) continue to monitor these volcanoes closely and will issue additional updates and changes in alert level as warranted.

For images, graphics, and general information on Cascade Range volcanoes: http://volcanoes.usgs.gov/observatories/cvo/
For seismic information on Oregon and Washington volcanoes: http://www.pnsn.org/volcanoes
For information on USGS volcano alert levels and notifications: https://volcanoes.usgs.gov/vhp/notifications.html



Featured image: Current US Forest Service Mount St. Helens VolcanoCam image.


Advertisements

Guest Video: The Biggest Eruption of the 20th Century

This 2012 presentation tells the story of the VEI 6 eruption of Katmai/Novarupta in 1912.

Alaskans are still experiencing ashfall from that eruption’s deposits whenever the wind is right, most recently in November 2017 according to the Smithsonian.

This huge eruption was unusual in that it was associated with a caldera collapse in nearby Katmai Volcano.

The Internet Archive has the 1922 National Geographic Society report on their expedition to the volcano here.

The Alaska Volcano Observatory monitors Katmai around the clock, but the only trouble the volcano has caused lately has been remobilized ash from the 1912 eruption.


Featured image: NASA