THIS SNOWPACK SUMMARY EXPIRED ON February 24, 2021 @ 9:04 am
Snowpack Summary published on February 22, 2021 @ 9:04 am
Issued by Jason Mozol - Bridgeport Avalanche Center

bottom line:

Unstable, wet loose snow on sun-exposed slopes are the main avalanche problem for the next few days. Clear skies, warming temperatures and steep terrain are the ingredients for wet loose avalanches.  Lingering wind slab avalanches remain possible to trigger in isolated terrain features at upper elevations on N-E-S aspects.

Avalanche Character 1: Loose Wet
Loose Wet avalanches occur when water is running through the snowpack, and release at or below the trigger point. Avoid very steep slopes and terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.

Warm temperatures and clear skies will add energy to the snowpack, melting snow on the surface and resulting in the possibility for loose wet avalanches. E-S-W aspects will be of most concern as direct sunlight affects them throughout the day. These avalanches will likely be small, avoid steep south facing slopes with abrupt slope changes where snow could pile up and injure a person. Wet loose avalanches can be avoided by moving off terrain with wet snow to areas that have received less solar radiation.

Avalanche Character 2: 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.

New snow and strong wind last Friday into Saturday formed small wind slabs on N-E-S aspects, with slow healing northerlies of greatest concern. They are most likely to be encountered in upper elevation terrain such as loaded chutes, gullies and bowls. Be aware of locations that look smooth, rounded or below existing cornices.  

Snowpack Discussion

Today, it is important to pay attention to warming surface snow. Above freezing temperatures, strong sun and light winds will allow this problem to progress during the day. E aspects will warm first followed by S and W aspects as the sun makes its way across the sky.  


Continued observation of basal facets on NW-N-E aspects has not given indications that this weak layer is reactive. Snowpit tests last week targeting this layer support the notion that it is unlikely to be triggered. Still, persistent weak layers can be tricky as they are difficult to predict, usually fail without giving signs of instability and take a long time to completely heal. Avoiding likely trigger points, such as convex rolls and shallow snow near trees and rocks, will further decrease the likelihood of encountering this problem. 

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 27 deg. F.
Max. temperature in the last 24 hours: 41 deg. F.
Average wind direction during the last 24 hours: E
Average wind speed during the last 24 hours: 5-10 mph
Maximum wind gust in the last 24 hours: 20 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 95 inches

High pressure today and tomorrow will bring mild weather and light winds with plenty of sun. As the week progresses, that high pressure will be replaced with a cold front, cloudier skies and winds from the NE. 

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Monday Monday Night Tuesday
Weather: Sunny Clear Mostly cloudy
Temperatures: 38-44 deg. F. 22-27 deg. F. 35-43 deg. F.
Wind direction:
Wind speed: Light Light Light
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Monday Monday Night Tuesday
Weather: Sunny Clear Mostly cloudy
Temperatures: 32-38 deg. F. 17-22 deg. F. 27-35 deg. F.
Wind direction: NE N
Wind speed: 15-20mph, gust to 35mph Light 15-30mph, gusts to 50mph
Expected snowfall: 0 in. 0 in. 0 in.

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.