Large Mount Baker debris Avalanche this fall
October 29, 2013
by Steve Malone
Yesterday a local pilot and well known mountain photographer, John Scurlock reported spotting avalanche debris in the east breach of Shurman Crater on Mount Baker. To quote John's e-mail: "the upper east face of Sherman Peak on Mount Baker had shed its huge buildup of snow in an avalanche that went down into the east breach of Sherman Crater and then on down Boulder Glacier". John provides us with his impressive photo of the source zone for this avalanche taken on Oct 27, 2013. (All photos are copy righted by John Scurlock)
The seismograms for this event are from MBW, located about 6 km due west of Mount Baker and SHUK, located at the Mount Baker ski area about 11 km to the east-northeast.
MBW PDT Oct, 21, 2013
SHUK PDT Oct 21, 2013
We also show spectrograms for these two stations and for RPW, located about 24 km to the southeast. Spectrograms show the frequency content of the seismic signals (vertical axis) versus time (horizontal axis) with the strength of the signal as colors going from blue (weak signal) to red (strong signal). This spectrogram is a preview of the type of information we will be routinely providing on our PNSN web pages in the future.
2006 Similar Avalanche
It is interesting to compare this event with a previous known similar event that took place on Jul. 25, 2006. Again, photos by John Scurlock show that the source zone is very similar to the recent avalanche but may have involved less material. Note the size of the debris pile in the east breach.
The amplitude on the seismograms from station MBW is consistent with the recent event being larger. The duration of the signal is similar but the amplitude of the 2006 event is significantly less.