THIS SNOWPACK SUMMARY EXPIRED ON December 26, 2018 @ 7:38 am
Snowpack Summary published on December 24, 2018 @ 7:38 am
Issued by Ryan Lewthwaite -

bottom line:

Santa is bringing us fresh snow, strong winds & increasingly hazardous avalanche conditions. If we accumulate a foot of snow with the forecasted W-SW strong ridgetop winds, slopes on aspects that face NW-N-E-SE will be prone to wind slab avalanches. Give storm slabs time to settle before you consider the riding "open season". Deployment of sleds from the main trailhead (people's gate) is reccomended. Carbide hill is rather bare but the upper parking lot is deep with nowhere to turn around.

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.

Shifting W to SW winds, with strong ferocity, will collect snow in leeward terrain features. These deposits are already dramatic in proportion & have several layers of windpack in their complex structure. Avoid steep slopes on aspects facing NW-N-E-SW as they will hold new soft wind slabs later today.

Avalanche Character 2: Storm Slab
Storm Slab avalanches release naturally during snow storms and can be triggered for a few days after a storm. They often release at or below the trigger point. They exist throughout the terrain. Avoid them by waiting for the storm snow to stabilize.

A possible foot of fresh wind driven snow could fall in the next 24 hours.These storm snow accumulations could be variable on slopes that are over 30 degrees, sun encrusted, or firmly windpacked. Keep your riding horizon low in angle & search for protected meadows with the best conditions.   

Snowpack Discussion

The arrival of new snow accumulation this afternoon & evening will increase the avalanche potential. Well pronounced wind slabs will continue to develop on already loaded & complex leeward terrain features on slopes facing N-E. With the shifting winds throughout today these wind slabs could be active on the NW & SE aspects as well. The overall pack yesterday had gained some strength, but this new snow variable should invigorate the avalanche hazard.

recent observations

Yesterdays conditions were good in the alpine. Visibility was low with an inch of accumulation throughout the ride. Soft snow resides above a supportable base above 8500'. Small avalanches, on steep isolated wind features, were barely noticable through the dense clouds.

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 31 deg. F.
Max. temperature in the last 24 hours: 38 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: mph
Maximum wind gust in the last 24 hours: mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 28 inches
weather

Sporatic snow showers yesterday deposited a fresh inch. Todays late morning storm arrival could bring significant accumulations around 12" by Christmas day. Expect robust winds starting from the West & shifting Southwest, then shifting back to the West, with gusts over 60 mph at ridgeline. Colder temperatures with strong winds tonight could leave fresh winds deposits on aspects NW-N-E-SE.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Monday Monday Night Tuesday
Weather: Mostly cloudy with snow showers. Snow levels below 7000' Cloudy with snow. Snow levels below 7000' Mostly cloudy with a chance of snow showers. Snow levels below 7000'
Temperatures: 36 to 42 deg. F. 16 to 22 deg. F. 24 to 29 deg. F.
Wind direction: Southwest Southwest Northwest
Wind speed: 15 to 25 mph; gusts to 35 mph increasing to 50 mph later 15 to 30 mph; gusts to 55 mph decreasing to 45 mph after midnight 15 to 25 mph; gusts to 45 mph
Expected snowfall: 2 in. 6 to 10 in. 1 in.
For above 10000 ft.
  Monday Monday Night Tuesday
Weather: Mostly cloudy with snow after noon. Snow levels below 7000' Cloudy with snow! Snow levels below 7000' Mostly cloudy then becoming partly cloudy. Chance for snow showers. Snow levels below 7000'
Temperatures: 29 to 34 deg. F. 9 to 14 deg. F. 20 to 25 deg. F.
Wind direction: West shifting Southwest Southwest shifting West North
Wind speed: 15 to 30 mph; gusts to 40 mph after shift 25 to 35 mph; gusts to 60 mph later 30 to 45 mph after shift 25 to 35 mph; gusts to 65 mph 20 to 35 mph; gusts to 55 mph
Expected snowfall: 2 in. 8 to 12 in. 1 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.