Snowpack Summary published on March 27, 2021 @ 8:19 am
Issued by Arden Feldman - Bridgeport Avalanche Center

bottom line:

Strong spring sunshine, light winds, and very warm temperatures will heat up the snowpack today. Loose wet avalanches will become likely on the southern half of the compass at all elevations. Look out for signs of wet snow instability like unsupportable wet snow and rollerballs. Isolated stubborn wind slabs are still lingering above tree line as well. Evaluate snow and terrain carefully to identify features of concern.

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.

Sunny skies, light winds, and very warm temperatures will make loose wet avalanches likely on steep E-S-W aspects at all elevations today. Snow surfaces will heat up starting with easterly and southerly aspects and move to westerly aspects later in the day. Timing is critical during these springtime conditions. With the high sun angle, the snow on northerly aspects could heat up today too. Keep track of how wet the snow is getting beneath you. If you are stepping in past your ankles in wet snow or seeing rollerballs, avoid steep slopes. These avalanches will be largest in sustained steep terrain and be especially hazardous around rocks, cliffs, and terrain traps. Remember you can move to a different slope aspect to find colder snow or choose lower angled slopes without steep slopes above to avoid the problem.

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.

Triggering a wind slab is unlikely today, but you could still find a lingering stubborn one in an isolated spot above tree line. These could be found on all aspects from the recent shifting winds. There a multiple layers of wind slabs; they may look like a classic smooth, rounded pillow in the fresh snow, but others could be older harder slabs hidden underneath. They may be hard to see by just looking at the snow surface. Avoid steep slopes where you see cracking and collapsing and think of the potential consequences of even a small avalanche in extreme terrain.

Snowpack Discussion

It’s going to be a beautiful spring weekend. Remember to stay attentive to the avalanche conditions even when the weather is gorgeous out. Continue to use good judgement and decision making skills. When the snow gets too wet, find colder snow or lower slope angles. 

The weather tomorrow looks sunny and even warmer with winds increasing in the afternoon. Thankfully tonight’s temperatures are forecasted to be cool enough to freeze snow surfaces at all elevations. Tomorrow, expect similar avalanche conditions to today.

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 28 deg. F.
Max. temperature in the last 24 hours: 33 deg. F.
Average wind direction during the last 24 hours: NE -> SE
Average wind speed during the last 24 hours: 5-10 mph
Maximum wind gust in the last 24 hours: 17 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 104 inches

A warm and dry weekend is forecasted with high pressure overhead. During the day, temperatures will climb into the 40s and 50s in the mountains, and 60s in the valleys. Tonight, temperatures are forecasted to dip below freezing. A dry cold front will move through early Monday bringing increased winds and cooler temperatures until we return to warmer weather later in the week.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Saturday Saturday Night Sunday
Weather: Sunny. Clear. Sunny.
Temperatures: 43 to 53 deg. F. 24 to 30 deg. F. 47 to 57 deg. F.
Wind direction: Southwest
Wind speed: Light winds. Light winds. Light winds becoming southwest around 15 mph with gusts to 25 mph in the afternoon.
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Saturday Saturday Night Sunday
Weather: Sunny. Clear. Sunny.
Temperatures: 35 to 45 deg. F. 18 to 23 deg. F. 37 to 47 deg. F.
Wind direction: North Southwest West
Wind speed: Around 15 mph in the morning becoming light. Light winds becoming southwest around 15 mph after midnight. 15 to 20 mph with gusts to 30 mph.
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.