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ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Thursday, November 25, 2021, 12:16 PM AKST (Thursday, November 25, 2021, 21:16 UTC)


SEMISOPOCHNOI VOLCANO (VNUM #311060)
51°55'44" N 179°35'52" E, Summit Elevation 2625 ft (800 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Low-level eruptive activity continues at Semisopochnoi volcano. Small explosions were detected over the past day. Low-level ash emissions were observed in web camera views. No significant activity was observed in partly cloudy satellite data over the past day.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft above sea level have characterized the recent activity. Small explosions may continue to occur and could be difficult to detect, especially during poor weather conditions.

Semisopochnoi is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.


GREAT SITKIN VOLCANO (VNUM #311120)
52°4'35" N 176°6'39" W, Summit Elevation 5709 ft (1740 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Seismicity remains slightly above background levels. No significant activity was observed in satellite and web camera views over the past day. Elevated surface temperatures from the surface of the active lava flow were observed in satellite data.

Lava effusion continues at a slow rate. It is possible that explosive activity could occur with little or no warning.

Great Sitkin is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.


PAVLOF VOLCANO (VNUM #312030)
55°25'2" N 161°53'37" W, Summit Elevation 8261 ft (2518 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Unrest continues at Pavlof Volcano. Seismic data remains elevated and small explosions were detected in infrasound data over the past day. No significant activity was observed in mostly cloudy satellite and web camera views.

Small explosions accompanied by low-level ash emissions could happen at any time, and are typically a hazard in the immediate vicinity of the summit. The level of unrest at Pavlof can change quickly and the progression to more significant eruptive activity can occur with little or no warning.

Pavlof is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.


KATMAI VOLCANO (VNUM #312170)
58°16'44" N 154°57'12" W, Summit Elevation 6716 ft (2047 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Strong northwesterly winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes have picked up loose volcanic ash erupted during the 1912 Novarupta-Katmai eruption and carried it to the southeast toward Kodiak Island this morning. The National Weather Service has issued a SIGMET for this low-level event and suggests that the maximum cloud height is 5,000 ft above sea level.

This phenomenon is not the result of recent volcanic activity and occurs during times of high winds and dry snow-free conditions in the Katmai area and other young volcanic areas of Alaska. No eruption is in progress. All of the volcanoes of the Katmai area (Snowy, Griggs, Katmai, Novarupta, Trident, Mageik, Martin) remain at color code GREEN.

Resuspended volcanic ash should be considered hazardous and could be damaging to aircraft and health. For more information on volcanic ash and human health, visit the following website: http://volcanoes.usgs.gov/ash/. Official warnings about these ash resuspension events are issued by the National Weather Service: https://www.weather.gov/afc/. Forecasts of airborne ash hazard to aircraft: https://www.weather.gov/aawu/. Volcanic Ash Advisories: https://www.weather.gov/vaac/. Forecasts of ash fall: http://www.weather.gov/afc. Air quality hazards and guidance from Alaska Department of Environmental Conservation, Division of Air Quality: http://dec.alaska.gov/Applications/Air/airtoolsweb/Advisories/Index


OTHER ALASKA VOLCANOES

Information on all Alaska volcanoes is available at: http://www.avo.alaska.edu.

For definitions of Aviation Color Codes and Volcano Alert Levels, see: http://www.avo.alaska.edu/color_codes.php

SUBSCRIBE TO VOLCANO ALERT MESSAGES by email: http://volcanoes.usgs.gov/vns/

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CONTACT INFORMATION:

Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF, dfee1@alaska.edu (907) 322-4085


The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.