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(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210920/1947Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A812
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Ash emissions from the ongoing eruption at Semisopochnoi continue this morning. Satellite images show an ash cloud up to 10,000 to 15,000 feet above sea level and extending approximately 60 miles (100 km) to the northwest through 19:30 UTC. Explosions were detected throughout the night and into this morning. The Aviation Color Code and Volcano Alert level remain at RED/WARNING.

The Alaska Volcano Observatory will continue to closely monitor all available data and provide updates as available.

Please visit the NWS Alaska Aviation Weather Unit for current information about the volcanic ash cloud forecast. https://www.weather.gov/aawu/sigmets
(12) Volcanic cloud height: 10,000 to 15,000 ft. asl
(13) Other volcanic cloud information: Ash observed in satellite extending 60 miles to the NW
(14) Remarks: Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

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

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu

AVO/USGS Volcanic Activity Notice

Volcano: Semisopochnoi (VNUM #311060)

Current Volcano Alert Level: WARNING

Current Aviation Color Code: RED

Issued: Monday, September 20, 2021, 11:47 AM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2021/A812
Location: N 51 deg 55 min E 179 deg 35 min
Elevation: 2625 ft (800 m)
Area: Aleutians

Volcanic Activity Summary: Ash emissions from the ongoing eruption at Semisopochnoi continue this morning. Satellite images show an ash cloud up to 10,000 to 15,000 feet above sea level and extending approximately 60 miles (100 km) to the northwest through 19:30 UTC. Explosions were detected throughout the night and into this morning. The Aviation Color Code and Volcano Alert level remain at RED/WARNING.

The Alaska Volcano Observatory will continue to closely monitor all available data and provide updates as available.

Please visit the NWS Alaska Aviation Weather Unit for current information about the volcanic ash cloud forecast. https://www.weather.gov/aawu/sigmets


Recent Observations:
[Volcanic cloud height] 10,000 to 15,000 ft. asl
[Other volcanic cloud information] Ash observed in satellite extending 60 miles to the NW
[Lava flow/dome] none
[Lava flow] none

Remarks: Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.

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

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



Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu

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.