Volcano Update from Archive



AVO/USGS Volcanic Activity Notice

Volcano: Redoubt (CAVW #1103-03-)

Current Volcano Alert Level: WATCH
Previous Volcano Alert Level: NONE

Current Aviation Color Code: ORANGE
Previous Aviation Color Code: NONE

Issued: Friday, April 3, 2009, 11:44 AM AKDT (20090403/1944Z)
Source: Alaska Volcano Observatory
Notice Number: 2009/A31
Location: N 60 deg 29 min W 152 deg 44 min
Elevation: 10197 ft (3108 m)
Area: Cook Inlet-South Central Alaska

Volcanic Activity Summary: The eruption of Redoubt Volcano continues. Over the past several days, the intensity of ash-production has decreased. Current observations indicate a lava dome is growing in the summit crater. Therefore, we are lowering the alert level and aviation color code.

The 2009 eruption is now characterized by continuous emission of steam, volcanic gas, and variable amounts of ash. These processes are occurring as effusion of lava in the summit crater produces a lava dome. While at this level of activity, trace amounts of ash and a perceptible volcanic haze layer may be intermittently present throughout south-central Alaska.

A growing lava dome is inherently unstable; a sudden dome collapse or explosion can occur with no warning and produce a more voluminous ash cloud that rises to elevations above 25,000 feet. If such an event is detected, AVO would issue appropriate warnings.

Remarks: Heavily ice-mantled Redoubt volcano is located on the western side of Cook Inlet, 170 km (106 mi) southwest of Anchorage and 82 km (51 mi) west of Kenai, within Lake Clark National Park. Redoubt is a stratovolcano which rises to 10,197 feet above sea level. Recent eruptions occurred in 1902, 1966-68, and 1989-90. The 1989-90 eruption produced mudflows, or lahars, that traveled down the Drift River and partially flooded the Drift River Oil Terminal facility. The ash plumes produced by the 1989-90 eruption affected air traffic and resulted in minor or trace amounts of ash in the city of Anchorage and other nearby communities.

Contacts: Tom Murray, Scientist-in-Charge, USGS
tlmurray@usgs.gov (907) 786-7497

Steve McNutt, Coordinating Scientist, UAF
steve@giseis.alaska.edu (907) 474-7131

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.
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:(20090403/1944Z)
(3) Volcano:Redoubt (CAVW# 1103-03-)
(4) Current Color Code:ORANGE
(5) Previous Color Code:
(6) Source:Alaska Volcano Observatory
(7) Notice Number:2009/A31
(8) Volcano Location:N 60 deg 29 min W 152 deg 44 min
(9) Area:Cook Inlet-South Central Alaska
(10) Summit Elevation:10197 ft (3108 m)
(11) Volcanic Activity Summary:The eruption of Redoubt Volcano continues. Over the past several days, the intensity of ash-production has decreased. Current observations indicate a lava dome is growing in the summit crater. Therefore, we are lowering the alert level and aviation color code.

The 2009 eruption is now characterized by continuous emission of steam, volcanic gas, and variable amounts of ash. These processes are occurring as effusion of lava in the summit crater produces a lava dome. While at this level of activity, trace amounts of ash and a perceptible volcanic haze layer may be intermittently present throughout south-central Alaska.

A growing lava dome is inherently unstable; a sudden dome collapse or explosion can occur with no warning and produce a more voluminous ash cloud that rises to elevations above 25,000 feet. If such an event is detected, AVO would issue appropriate warnings.
(12) Volcanic cloud height:Unknown
(13) Other volcanic cloud information:Unknown
(14) Remarks:Heavily ice-mantled Redoubt volcano is located on the western side of Cook Inlet, 170 km (106 mi) southwest of Anchorage and 82 km (51 mi) west of Kenai, within Lake Clark National Park. Redoubt is a stratovolcano which rises to 10,197 feet above sea level. Recent eruptions occurred in 1902, 1966-68, and 1989-90. The 1989-90 eruption produced mudflows, or lahars, that traveled down the Drift River and partially flooded the Drift River Oil Terminal facility. The ash plumes produced by the 1989-90 eruption affected air traffic and resulted in minor or trace amounts of ash in the city of Anchorage and other nearby communities.
(15) Contacts:Tom Murray, Scientist-in-Charge, USGS
tlmurray@usgs.gov (907) 786-7497

Steve McNutt, Coordinating Scientist, UAF
steve@giseis.alaska.edu (907) 474-7131
(16) Next Notice:A new VONA will be issued if conditions change significantly or alert levels are modified. While a VONA is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu