60 Million-Ton Avalanche on Mt. Steele

Last week it became evident that a massive 45 to 50 megaton avalanche had occurred on Mount Steele in Canada’s Yukon Territory. Satellite images show that the slide ripped down the southeast flank of Mount Steele and was so large that it was initially detected by earthquake seismometers. The seismic data suggests that this rock avalanche had a peak velocity of about 130mph. The data also suggests that the slide lasted about 110 seconds.

Monday,  October 12 was the day of this massive slide and it’s crown was reported to be at an elevation of about 3350 m. It ran a total vertical distance of about 2200 m to the toe. 

The 2007 Mount Steele rock avalanche from Lipovsky et al. (2008)

The approximate location of the slide.