(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20170220/0307Z)
(3) Volcano:	Bogoslof (VNUM #311300)
(4) Current Color Code:	RED
(5) Previous Color Code:	ORANGE
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location:	N 53 deg 55 min W 168 deg 2 min
(9) Area:	Aleutians
(10) Summit Elevation:	492 ft (150 m)
(11) Volcanic Activity Summary:	A significant explosive eruption began at Bogoslof volcano at 02:08 UTC on 20 February (17:08 AKST on 19 February). Seismic and infrasound data show a series of short-lived explosive pulses through 02:45 UTC; seismicity has been quiet since then. Recent satellite images show a cloud as high as 25,000 ft asl. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING for Bogoslof volcano. Winds are carrying the cloud from Bogoslof to the southeast, towards Unalaska Island.
(12) Volcanic cloud height:	25,000 ft asl estimated by satellite
(13) Other volcanic cloud information:	Cloud moving towards southeast
(14) Remarks:	The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit, currently is in effect up to 25,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/ See http://www.weather.gov/afc/ for details on ash fall forecasts from the National Weather Service.
(15) Contacts:	Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497 Jeff Freymueller, Coordinating Scientist, UAFGI jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:

---

AVO/USGS Volcanic Activity Notice

Volcano: Bogoslof (VNUM #311300)

Current Volcano Alert Level: WARNING

Current Aviation Color Code: RED
Previous Aviation Color Code: ORANGE

Issued: Sunday, February 19, 2017, 6:07 PM AKST
Source: Alaska Volcano Observatory
Notice Number:
Location: N 53 deg 55 min W 168 deg 2 min
Elevation: 492 ft (150 m)
Area: Aleutians

Volcanic Activity Summary: A significant explosive eruption began at Bogoslof volcano at 02:08 UTC on 20 February (17:08 AKST on 19 February). Seismic and infrasound data show a series of short-lived explosive pulses through 02:45 UTC; seismicity has been quiet since then. Recent satellite images show a cloud as high as 25,000 ft asl. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING for Bogoslof volcano.

Winds are carrying the cloud from Bogoslof to the southeast, towards Unalaska Island.

Recent Observations:
[Volcanic cloud height] 25,000 ft asl estimated by satellite
[Other volcanic cloud information] Cloud moving towards southeast

Hazard Analysis:
[Ashfall] Trace of ash fallout on Unalaska Island possible.

Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit, currently is in effect up to 25,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/

See http://www.weather.gov/afc/ for details on ash fall forecasts from the National Weather Service.

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

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@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.

---