(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20111229/1655Z)
(3) Volcano:	Cleveland (VNUM #311240)
(4) Current Color Code:	ORANGE
(5) Previous Color Code:	YELLOW
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2011/A7
(8) Volcano Location:	N 52 deg 49 min W 169 deg 56 min
(9) Area:	Aleutians
(10) Summit Elevation:	5676 ft (1730 m)
(11) Volcanic Activity Summary:	A detached drifting ash cloud to approximately 15,000 ft ASL has been detected at Cleveland Volcano in satellite images from 1402 UTC, Dec 29. As of 1445 UTC the ash cloud was approximately 80 KM/50 miles moving ESE from the volcano. Based on the presence of an ash cloud, AVO has raised the aviation color code at Cleveland Volcano to ORANGE and alert level WATCH. Satellite data indicate that this is a single explosion event, however, more sudden explosions producing ash could occur with plumes exceeding 20,000 feet above sea level. Such explosions and their associated ash clouds may go undetected in satellite imagery for hours. However, in cooperation with the University of Washington, AVO has implemented a lightning alarm system that may detect significant ash-producing events within minutes of onset. If a large explosive event occurs, seismic signals may be recorded on AVO seismic networks at nearby volcanoes. There is no real-time seismic monitoring network at Cleveland. Additional information on Cleveland Volcano and the current activity may be found at this link: http://www.avo.alaska.edu/activity/Cleveland.php Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcano alert levels.
(12) Volcanic cloud height:	15,000 ft
(13) Other volcanic cloud information:	detached plume moving ESE from the volcano
(14) Remarks:	Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano's most recent significant eruption began in February, 2001 and it produced 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. The 2001 eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in January and June 2009.
(15) Contacts:	John Power, Scientist-in-Charge, USGS jpower@usgs.gov (907) 786-7497 Chris Nye, Acting Coordinating Scientist cnye@giseis.alaska.edu (907) 474-7430
(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

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AVO/USGS Volcanic Activity Notice

Volcano: Cleveland (VNUM #311240)

Current Volcano Alert Level: WATCH
Previous Volcano Alert Level: ADVISORY

Current Aviation Color Code: ORANGE
Previous Aviation Color Code: YELLOW

Issued: Thursday, December 29, 2011, 7:55 AM AKST
Source: Alaska Volcano Observatory
Notice Number: 2011/A7
Location: N 52 deg 49 min W 169 deg 56 min
Elevation: 5676 ft (1730 m)
Area: Aleutians

Volcanic Activity Summary: A detached drifting ash cloud to approximately 15,000 ft ASL has been detected at Cleveland Volcano in satellite images from 1402 UTC, Dec 29. As of 1445 UTC the ash cloud was approximately 80 KM/50 miles moving ESE from the volcano.

Based on the presence of an ash cloud, AVO has raised the aviation color code at Cleveland Volcano to ORANGE and alert level WATCH.


Satellite data indicate that this is a single explosion event, however, more sudden explosions producing ash could occur with plumes exceeding 20,000 feet above sea level. Such explosions and their associated ash clouds may go undetected in satellite imagery for hours. However, in cooperation with the University of Washington, AVO has implemented a lightning alarm system that may detect significant ash-producing events within minutes of onset. If a large explosive event occurs, seismic signals may be recorded on AVO seismic networks at nearby volcanoes. There is no real-time seismic monitoring network at Cleveland.

Additional information on Cleveland Volcano and the current activity may be found at this link:
http://www.avo.alaska.edu/activity/Cleveland.php

Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcano alert levels.



Recent Observations:
[Volcanic cloud height] 15,000 ft
[Other volcanic cloud information] detached plume moving ESE from the volcano

Remarks: Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano's most recent significant eruption began in February, 2001 and it produced 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. The 2001 eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in January and June 2009.

Contacts: John Power, Scientist-in-Charge, USGS
jpower@usgs.gov (907) 786-7497

Chris Nye, Acting Coordinating Scientist
cnye@giseis.alaska.edu (907) 474-7430

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

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