These observations document past conditions at a small and variable scale. They are not to be confused with an avalanche forecast. They come from a variety of sources. We can only vouch for the quality of those produced by the SAC forecasters and professional observers.
Date and time of observation or avalanche occurrence Location Media Observation made by
02/17/2017 - 11:00
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Wind loading and cornice formation on W aspect from the SE winds.Small reactive wind slab on W aspect, 8200', 2-6'' deep.Cracking and shooting cracks on wind loaded test slopes. Forecaster
11/12/2020 - 11:00
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Thin snowpack at 7800', E aspect, in below treeline terrain. Limited to no snow on southerly aspects. Previous NE/E wind scouring on the top of Andesite Peak Forecaster
12/14/2016 - 11:30
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Rain runnels existed up to Peak level (8200'). Forecaster
12/04/2016 - 13:00
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Guide
Tahoe Mountain Scho
11/18/2012 - 10:00
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Professional Observer
12/29/2018 - 14:15
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Visual outline of the Snowpack on a West Aspect Near Treeline @ 7600' Educator
Tahoe Mountain Scho
04/06/2022 - 10:30
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Good coverage and smooth surfaces exist on open E facing aspects on Andesite Ridge. 1-2 inches of soft wet corn snow had formed on the E aspects by 10:30 am. These slopes also still had a supportable 6-8 in thick frozen melt freeze crust below the wet surface snow. Very uneven snow surfaces existed in some areas. More dirt and debris continues to appear as the snow melts. Lots of dirt showing on the SW side of Castle Peak. Impressive amounts of debris exist on the snow surface in wooded areas. Forecaster
04/16/2018 - 11:00
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Small wind slab triggered by large cornice drop on a ENE facing test slope at 8040 ft. See video. Small 1 to 4 inch slab triggered on an E facing test slope @ 8040 ft. that had just received a short period of sun-exposure The other side of the small slab triggered on the E facing test slope. New snow and some wind-loading filling in the skin track @ 8160 ft. About 30 cm (1 ft) of new snow resting on top of a moist crust on top of wet snow in a meadow at 7500 ft. Forecaster
01/06/2016 - 10:30
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Forecaster
12/21/2017 - 11:00
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Wind transport of snow at treeline.The maximum extent of cracking seen today in new wind slabs on W-NW aspects. Small 1.5m crack off tip of right ski.Cracking of undercut wind slab on NE aspect at treeline. Forecaster
12/21/2018 - 11:00
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Wind loaded test slopes showing unreactive slabs. Minor cracking on old/new snow interface while breaking trail. Skier triggered rollerballs after about 2 hrs of very light rain. Forecaster
12/28/2022 - 11:30
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Small cornice collapse on Andesite Ridge PS 5-10 cm at all elevations Guide
International Alpine Guid
12/11/2022 - 12:00
Avalanche Observation 		Andesite Peak
Donner Summit Area 		Crown from a natural wind slab avalanche in small terrain. Natural storm slab avalanche on small test slope. Intentionally skier triggered storm slab avalanche on small test slope. Forecaster
12/12/2020 - 15:00
Snowpack Observation 		Andesite Peak
Donner Summit Area 		Educator
Alpenglow Expeditio
02/16/2017 - 11:30
Avalanche Observation 		Andesite Peak
Donner Summit Area
Split-board kicks triggered a refrigerator sized cornice failure onto the wind loaded test slope. This resulted in a 12-14 inch deep wind slab failure.
The other side of the wind slab that resulted from the cornice drop.
Wind slab cracking in an undercut wind-loaded slope
 Forecaster

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