Okmok Eruption...

The image above is of the eruption cloud from Okmok Volcano, taken at 5:30pm AKDT, July 12th, from an estimated height of 20,000 ft above sea level. Cloud tops were estimated at 30,000 to 35,000 feet. It was copied from the Alaska Volcano Observatory's website (http://www.avo.alaska.edu/) as are all of the other images used in this post.

While volcanoes aren't new or strange to most Alaskans, they sure are a lot of both to me! Since I began training with the Center Weather Service Unit in late May, I have been "warned" about the "mass chaos" that takes place here when a volcano errupts into the air space we forecast for. I have been experienceing such "chaos" since Saturday - when a peak in the Okmok Caldera on the Aleutian Island of Umnak erupted.

Okmok errupted around noon on Saturday, July 12th - an hour before my shift began! Most of the time, volcanos give some "warning" before eruptions. Most of the active volcanos in Alaska are seismically monitored and increased seismic activity can indiate that a volcano is about to errupt. All active volcanos are given a status color, based on current activity and the possibility of an eruption.

Okmok was "green" before it errupted, as there was no increased seismic actvity to give anyone a warning.

Because my office is located in an air route traffic control center, I deal directly with air traffic controllers and their supervisors. I don't write any of the volcanic ash advisories or warnings... but I have to use satellite and weather model data to verify them... then explain to the controllers what is going on with the volcano and where the ash is moving. I was never taught volcanic ash forecasting... this was my crash course!

The latest statement on the Okmok volcano says: "Based on past eruptions at Okmok and our analysis of the current episode of activity, we would expect this event to continue for several weeks and possibly longer. The position of the vent in the eastern caldera adjacent to a shallow lake suggests that water will continue to play a role in increasing the explosivity of the eruption resulting in significant ash and steam production. If the eruption follows patterns of previous Okmok events, lava will eventually reach the surface to form lava fountains, spatter accumulations, and possibly a lava flow. It is also possible that explosivity could intensify at any time."

Here are a couple more images that I thought were cool...

The image above was taken Sunday by a flight attendant on an Alaska Airlines jet... I think the plane was en route to Adak, Alaska  in the Western Aleutians. 

This is the Okmok Caldera, as viewed from an Alaska airlines jet in June of 2007.  The caldera is nearly circular, over a half mile deep, and about 6 miles wide.  The current caldera formed about 2000 years ago; since then, numerous eruptions have occured from many cones, peaks, and craters on the caldera floor.  Before the eruption on Saturday, Okmok last erupted in 1997.

The Alaska Volcano Observatory has lots of other cool images...

http://www.avo.alaska.edu/volcanoes/volcimage.php?volcname=Okmok