THIS SNOWPACK SUMMARY EXPIRED ON December 30, 2018 @ 7:00 am
Snowpack Summary published on December 28, 2018 @ 7:00 am
Issued by Ryan Lewthwaite -

bottom line:

A retreat of Tuesday's Christmas storm has left us with 5-8" of newly wind transported snow. Winds of Gale ferrocity from the North & East have deposited snow on Leeward aspects facing South & West. The primary concern today is the recently formed wind slabs at & above treeline which are variable in their density & strength. Have your rescue gear on your person & not attached to the snowmobiles tunnel. If your sled become buried, your ability to companion rescue greatly decreases. We encourage you to come practice your rescue skills with us at our beacon park. Good snow exists all the way to our trailhead at People's Gate, see you there!

Avalanche Character 1: Wind Slab
Wind Slab avalanches release naturally during wind events and can be triggered for up to a week after a wind event. They form in lee and cross-loaded terrain features. Avoid them by sticking to wind sheltered or wind scoured areas.

Uniquely directional & up to Gale force winds have been active in the Eastern Sierra mountains with the arrival of this Christmas storm. North & Easterly winds have dramatically sculpted the snow & loaded some aspects & terrain features on the South & West. Yesterdays slabs ranged from soft to supportable over a very small area. The elongated fetch of transported snow has an ability to cast wind slabs much lower on the slopes, increasing a travelers ability to remotely trigger avalanches.

Snowpack Discussion

We are reporting 5.5-8" of new snow associated with this recent Christmas storm. Uncommon strong winds from the North & East have loaded & crossloaded terrain features facing South & West. Warm temperatures & rain with this system have created good bonding between the new & old snow surface. A gambit of precipitation types have fallen during the snows duration, mostly notably rain & graupel changing the snows surface below 8000'. 

recent observations

Swirling strong winds yesterday were transporting snow to places that have been previously scoured. Well defined cornices & drifts are scattered in irregular fashion from ridgelines into low lying meadows. This storm arrived warm & blustery with rain below 7500'. Associated with this storm a variety of precipitation forms were observed including: Stellars, Wind-Broken Particles, Rime & Rimed Particles, Rain, & Graupel. Sublimation of wind transported snow was also observed. The right-side-up nature of the storm has left some well-bonded new snow to the old snow surface. We have searched for new avalanche activity but have not seen anything substantial.

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 11 deg. F.
Max. temperature in the last 24 hours: 19 deg. F.
Average wind direction during the last 24 hours: East & North
Average wind speed during the last 24 hours: Moderate mph
Maximum wind gust in the last 24 hours: Gale mph
New snowfall in the last 24 hours: 1 inches
Total snow depth: 30 inches
weather

A few lingering snow showers will pass over us this morning with trace accumulations. Strong to Gale force winds will be persistent out of the North. Clouds will decrease this afternoon as the cold front moves out of our area. Very cold & windy conditions tonight with negative wind chill temperatures & clear skies.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Friday Friday Night Saturday
Weather: Partly cloudy then becoming sunny with isolated snow showers. Clear Sunny
Temperatures: 17 to 23 deg. F. 2 to 8 deg. F. 34 to 39 deg. F.
Wind direction: North North North
Wind speed: 15 to 25 mph; gusts to 80 mph decreasing to 60 mph in the afternoon 15 to 25 mph; gusts to 50 mph 10 to 15 mph; gusts to 45 mph with decreasing afternoon winds
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Friday Friday Night Saturday
Weather: Partly cloudy then becoming sunny with isolated snow showers in the morning. Clear Sunny
Temperatures: 15 to 21 deg. F. 2 to 3 deg. F. 30 to 35 deg. F.
Wind direction: North North North
Wind speed: 40 to 60 mph decreasing to 30 to 50 mph later; gusts to 85 mph 30 to 45 mph; gusts to 65 mph 25 to 40 mph shifting to the Northeast 20 to 30 mph later, gusts to 60 mph
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

This snowpack summary applies only to backcountry areas in the Bridgeport Winter Recreation Area. Click here for a map of the area. This snowpack summary describes general avalanche conditions and local variations always occur. This snowpack summary expires in 48 hours unless otherwise noted. The information in this snowpack summary is provided by the USDA Forest Service who is solely responsible for its content.