THIS SNOWPACK SUMMARY EXPIRED ON March 14, 2021 @ 9:34 am
Snowpack Summary published on March 13, 2021 @ 8:34 am
Issued by Jason Mozol - Bridgeport Avalanche Center

bottom line:

Northerly winds and strong sunshine today will create heightened avalanche conditions. The northerly winds continue to build fresh wind slab avalanches on E-S-SW aspects near and above tree line. Additionally, the sun will rapidly heat the fresh snow on E-S-W facing slopes at all elevations. Be aware of both natural and human triggered loose wet avalanches. Don’t fall prey to the powder panic; carefully evaluate snow and terrain and identify features of concern.

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.

6-12” of snow has fallen over the last several days with shifting winds. Northerly winds continue to drift the recent snowfall into wind slabs on E-S-SW aspects near and above tree line. These wind slabs will be sensitive today and solar heating may make them even more unstable. Also consider that a small loose wet avalanche could trigger a larger wind slab. Lingering wind slabs may still be present on northerly aspects as well from the previous strong southerly winds. Wind slabs are commonly found below ridgelines and in cross loaded gullies. Wind slabs often appear smooth and rounded, and cracking and collapsing are common signs of them. If you see signs of instability, choose lower angled slopes.

Avalanche Character 2: 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.

Today’s strong March sunshine will heat up the 6-12” of recent snow on E-S-W aspects at all elevations. Loose wet avalanches are likely and will slide easily on the old hard and slick snow surfaces. The top ~6” of the new snow is soft and low density. Fresh, low density snow is especially prone to heating up quickly and being extra sensitive to loose wet avalanching. Loose wet avalanches could fail naturally today, so make sure to be aware of the terrain above you. Keep track of the warming snow and watch for signs of instability like rollerballs and natural avalanches. Move to lower angle slopes or find colder snow when you see these signs.

Snowpack Discussion

Powder fever will be high today with fresh snow and plentiful sunshine. Don’t forget about the heightened avalanche conditions while out enjoying the backcountry. When you see signs of instability, remember that lower angled slopes will be fun to ride too. Avalanche conditions should be less sensitive tomorrow, but continue to look out for signs of unstable snow. Additional snowfall is forecasted for Sunday night into Monday.

recent observations

8-12” of snow and shifting winds over the last few days. The snow fell on widespread hard/slick surfaces and near surface facets on protected northerlies. Minor cracking has been observed in the fresh snow near tree line with more wind effect in the alpine. 

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 17 deg. F.
Max. temperature in the last 24 hours: 21 deg. F.
Average wind direction during the last 24 hours: N
Average wind speed during the last 24 hours: 5-20 mph
Maximum wind gust in the last 24 hours: 33 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 94 inches
weather

Drier and warmer weather is forecasted for most of the weekend. The next storm rolls in Sunday night with increased winds and up to a foot of snowfall.

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 Partly cloudy then becoming mostly cloudy.
Temperatures: 31 to 39 deg. F. 17 to 22 deg. F. 35 to 45 deg. F.
Wind direction: Northwest West Southwest
Wind speed: 15 to 25 mph with gusts to 45 mph. Around 15 mph. Gusts up to 35 mph decreasing to 25 mph after midnight. 15 to 20 mph. Gusts up to 30 mph increasing to 45 mph in the afternoon.
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Saturday Saturday Night Sunday
Weather: Sunny. Clear Partly cloudy then becoming mostly cloudy.
Temperatures: 23 to 31 deg. F. 13 to 18 deg. F. 27 to 35 deg. F.
Wind direction: Northwest West Southwest
Wind speed: 20 to 35 mph with gusts to 50 mph. 15 to 25 mph. Gusts up to 40 mph decreasing to 30 mph after midnight. 15 to 25 mph. Gusts up to 30 mph increasing to 40 mph in the afternoon.
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.