Quick report
We started out on Elephant's Hump today. Our obs were cut short at 11:15 am when we received a notification from Alpine County SAR that an snowmobile triggered avalanche had occurred. We diverted to that avalanche site 2 miles away out on the Forestdale Divide. See the avalanche tab for more info on that avalanche.
Prior to cutting our ob short, we dug two snowpits to assess persistent instability. The first pit on a NW aspect near 8,100' revealed no signs of instability. The second pit on a NW aspect near 8,400' revealed indications of persistent instability.
With our diversion to the site of the snowmobile triggered persistent slab avalanche, we covered 6 miles on skis today across N-NE-E-SE aspect terrain and did not encounter any snowpack collapses or whumpfs.
Several size D2 to D3 avalanches visible in the area from Elephant's Back south to Forestdale Divide. This included several older avalanches from the storm cycle and one size D3 persistent slab avalanche triggered by a snowmobile today.Weather
- Cloud Cover
- clear
- Wind Loading
- none
- Snow Avail For Transport
- moderate amounts
Clear skies and light winds.
Snowpack
Pit #1 was on NW aspect terrain near 8,100'. ECTN-24 within the recent storm snow. Pit #2 was on NW aspect terrain near 8,400'. ECTP-10 within the recent storm snow (down 25 cm) and ECTP-22 on facets (down 80 cm) just below the upper most rain crust. We dug down to the old Jan 31 near surface facet layer in both pits. The Jan 31 facets were dry to moist at F to 4F-. We did not get any ECT failures on the Jan 31 layer due to the strength of the rain crusts above.
Avalanche
- Size
- D3
- Aspect
- N
- Trigger
- AM
- Elevation
- 9300 ft
This avalanche was reported to 911/SAR from afar by a group of skiers who saw two snowmobiles on the slope and the avalanche in motion. SAC forecasters who were working in the area arrived on scene before SAR and the CHP helicopters. The forecasters swept the debris field, finding no people, snowmobiles, parts, personal effects, footprints, or transceiver signals in the area. It appeared that the triggering party had left the area, with no way of knowing that a SAR response was in progress.