Small avalanches on Cisco Butte

Location Name: 
Cisco Butte, West Face and Gullies
Donner Summit Area
Date and time of avalanche (best estimate if unknown): 
Sat, 01/05/2013 - 09:00
Location Map: 
United States
39° 18' 36.9396" N, 120° 33' 47.0304" W

Red Flags: 
Recent loading by new snow, wind, or rain

Observation made by: Public
Avalanche Observations
Avalanche Type: 
Trigger type: 
Other - explain below
Crown Height: 
1 ft
Weak Layer: 
Old Snow
Avalanche Width: 
Above Treeline
6 200ft.
Bed Surface: 
Old Snow
Avalanche Length: 
Number of similar avalanches: 
Number of people caught: 
Number of partial burials: 
More detailed information about the avalanche: 

We came to climb the west gully of Cisco Butte at the Eagle Lakes Exit off I-80. On the way up that morning we noticed a hard layer underneath the new snow. It was below freezing and the whole face was in the shade. As we began our climb, we decided to go up a short gully before the big one to practice snow climbing and test the snow conditions. We gathered behind a boulder as one climber (me) went up into the gully to lead the way. Suddenly the lower slope all around us released and slid. The snow just at this place was harder underneath as well as being overlaid by a layer of more slablike snow, probably created from wind that dumped the snow from slopes above into this gully. There was no obvious bed surface like this only a little ways down the slope, so we realized we had climbed up into these bad conditions. It was suprising that the conditions were different such a little distance downslope.

We decided to see how localized these conditions were, and if we could get the rest of the gully to go. With everyone out of the way, I went up to the crown and probed around to see if the rest of the gully was as volatile. It was a short gully - only about 40 feet long - with a plateau above it and no other danger of avalanching from above, so we deliberately set off this next one. It turned out to be about twice as large. Near the end of the slide I could not hold my stance at the edge of the gully anymore and was swept downslope. I was never buried and was able to stay above it the whole way, and easily extricated myself from the slide when it stopped about 150 feet downslope. We estimated the angle to be about 40 degrees. Still, we were surprised at the strength of the slide.

We decided to test the slopes one more time to see if there was anyway to ascend the mountain from this side. With everyone else behind trees, I went just a little ways above the last tree towards a cliffy area on the west face. This was about 200 yards north of the gully of where the other two slides occurred. We noticed the old hard layer was very pronounced on this face so expected that it might slide again, but the layer of new snow on the top was merely inches. Sure enough, when I was almost at the top of where this slope terminated at the bottom of the cliffs, the new layer slid again, funnelling all the way to the stream bottom. It was only a foot or two deep and the crown was very small, in some places even non-existent. This final test concluded our experiments - this mountain on this aspect today was too dangerous to attempt. 

Hope this helps other climbers / snow enthusiasts. The avalanche danger was low. Localized conditions make all the difference. This face and gully were cold, west-facing, with an older layer of snow at varying hardness, overlaid by a cold, most unconsolidated layer of new snow. The angle was right in the zone between 35-42 degrees. Always test slopes before you get committed. 

Weather Observations
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Below Freezing
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: