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Great Sitkin: Color Code ORANGE Alert Level WATCH
Local time: September 22, 2023 0305 AKDT (September 22, 2023 1105 UTC)
GREAT SITKIN LINKS

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COLOR CODE TIMELINE

CODE DEFINITIONS
ORANGE: Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, OR eruption is underway with no or minor volcanic-ash emissions [ash-plume height specified, if possible].
WATCH: Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, OR eruption is underway but poses limited hazards.
More information on color/alert definitions
GREAT SITKIN UPDATES
ORANGE/WATCH 09-21-2023 12:23 AKDT - Daily Update
ORANGE/WATCH 09-20-2023 12:06 AKDT - Daily Update
ORANGE/WATCH 09-19-2023 12:18 AKDT - Daily Update
ORANGE/WATCH 09-18-2023 12:31 AKDT - Daily Update
ORANGE/WATCH 09-17-2023 12:39 AKDT - Daily Update
ORANGE/WATCH 09-16-2023 12:25 AKDT - Daily Update
ORANGE/WATCH 09-15-2023 13:07 AKDT - Weekly Update
ORANGE/WATCH 09-14-2023 11:46 AKDT - Daily Update

All Great Sitkin Reports

Color Code and Alert Level Definitions

ASHFALL AND ASH CLOUD FORECASTS: MODEL OUTPUT
Mathematical models developed by the USGS forecast various aspects of how a volcanic ash plume will interact with wind—where, how high, and how fast ash particles will be transported in the atmosphere, as well as where ash will fall out and accumulate on the ground. AVO runs these models when a volcano is restless by assuming a reasonable hypothetical eruption, to provide a pre-eruptive forecast of areas likely to be affected. During an ongoing eruption, AVO will update the forecast with actual observations (eruption start time and duration, plume height) as they become available. Click on individual graphics to learn more.
ASHFALL FORECASTS
ASHFALL FORECAST
REPORTED ASHFALL

ASH CLOUD FORECASTS (AIRBORNE):
CLOUD HEIGHT
CLOUD LOAD
THESE PRODUCTS MAY NOT BE CURRENT.
During an actual eruption, see National Weather Service forecasts of airborne ash hazard to aircraft (SIGMETS: https://weather.gov/aawu/ and Volcanic Ash Advisories: https://weather.gov/vaac) as well as forecasts of ash fall: https://weather.gov/afc.
INSTRUMENT DATA

SELECTED IMAGES
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Great Sitkin index map
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June 5, 2021, M. Zelenevich
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May 30, 2021, S. Rhodes
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May 25, 2021, L. Flynn, USFWS
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May 25, F. Spitler
View all images of this event
LINKS
Contact AVO Privacy Accessibility Information Quality FOIA
URL: www.avo.alaska.edu/activity/GreatSitkin.php
Page modified: December 21, 2022 15:07
Contact Information: AVO Web Team

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