Image courtesy of Calvin Hall. Taken 3/28/2009 during an eruption at
10:59 AM3:28 PM.
UPDATE 4/2/2009 at 11 AM Pacific: I’m moving this up from the comments, but Eruptions reader Doug Cole pointed out (and I have no idea how I missed this) that Redoubt has a new webcam! This one is at the DFR seismic station, ~8 miles / 12 km northeast of the volcano. Great views on it today showing the extent of the ash around Redoubt and the steam/ash plume. This view will also be excellent if we get any dome collapse pyroclastic flows (see below).
After a week of explosions and ash fall, Redoubt seems to have quieter for the last couple days. There is still significant seismicity at the volcano as the webicorder can attest, but right now the volcano is just producing a steam plume that has some ash component and reaches 15-20,000 feet / 5-6 km depending on conditions. This doesn’t mean that Redoubt won’t produce any more large explosive eruptions, but rather than we’re getting into a period of lava extrusion, and the statement yesterday from AVO seems to confirm that: Thermal features observed in satellite images and in AVO helicopter-based thermal-infrared images from yesterday are most likely due to the extrusion of a lava dome in the summit crater. However, even with less explosions, Redoubt is still a Red/Warning alert.
As the lava dome grows, so does the chances of a collapse of said dome – explosively or gravitationally – which might then produce pyroclastic flows (similar to what we currently see at Soufriere Hills in Montserrat and Chaiten, Chile) and lahars generated as the pyroclastic flows melt the snow/glaciers on Redoubt and mix with water in the rivers/streams coming off the volcano. When this might happen is anyone’s guess and they might not even occur – the dome that formed in the Mt. Saint Helens crater during the 2004-08 eruptions didn’t produce much in the way of dome collapse block & ash flows .
(Please note that now that I’ve said that the volcano has “settled down”, we can almost guarantee it will do something exciting today.)