THIS SNOWPACK SUMMARY EXPIRED ON February 28, 2019 @ 7:40 am
Snowpack Summary published on February 26, 2019 @ 7:40 am
Issued by Ryan Lewthwaite -

bottom line:

Due to Strong & Gale force Southwest winds any soft or new snow will be transported to Wind Slabs on Lee aspects. These large drifts can be dangerous to travelers on steep slopes or adjacent to avalanche terrain. If rain falls on the new storm snow we could have a Loose Wet avalanche potential this afternoon. Stay in terrain that is low angle with no consequences to avoid large avalanches. 

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.

Strong to Gale force winds have been transporting soft & new snow to places near & below treeline. Drifts & Slabs have formed mainly on aspects NW-SE but swirling mountain winds may have put snow on all aspects. Triggering these reactive slabs could produce large avalanches able to destroy a truck & remove trees(D3).

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.

There is a possibility of rain with rising temperatures this afternoon. Rain on snow can cause Loose Wet avalanches that may be relatively small in size, depending on amount & intensity. Tomorrow there is another potential for rain during the afternoon hours. If enough rain falls we may be looking at Wet Slab avalanches being likely.

Snowpack Discussion

The surface of the snowpack is most concerning due to growing Wind Slab. Scouring of the higher alpine areas has put any new snow to near & below treeline areas as large deposits. These slabs may have the ability to propagate when you introduce yourself to a steep slope, causing large avalanches. Falling snow today has the potetial to turn to rain in the mid to lower elevations bringing with it more instability. Look for Loose Wet avalanches this afternoon if the rains conspire.

recent observations

~Yesterdays winds were Strong to Gale from the Southwest. Any soft snow has been transported to Lee aspects. Scalloping & scoured surfaces exist above treeline.

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 27 deg. F.
Max. temperature in the last 24 hours: 35 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: Strong mph
Maximum wind gust in the last 24 hours: Gale mph
New snowfall in the last 24 hours: 3 inches
Total snow depth: 94 inches
weather

Strong to Gale force Southwest winds will continue to be the biggest battle for traveling in the mountains today. Major gusts to 117 mph were reported yesterday! Blowing snow will make visibility very low & create wind deposits on Lee aspects. These Wind Slabs could be reactive to human triggering. Wind Slabs will grow as winds transport snow from the alpine to near & below treeline areas mostly being deposited on NW-SE aspects. Warming temperatures could bring rain into the scene this afternoon & we could possibly see Loose Wet avalanche activity at lower elevations.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Tuesday Tuesday Night Wednesday
Weather: Mostly cloudy with snow showers. Snow Level Below 7000' Mostly cloudy with snow showers. Snow Level Below 7000' Mostly cloudy with snow showers. Snow Level Below 7000'
Temperatures: 33 to 41 deg. F. 25 to 31 deg. F. 33 to 41 deg. F.
Wind direction: Southwest South Southwest
Wind speed: 30 to 45 mph; gusts to 80 mph 25 to 40 mph; gusts to 85 mph 15 to 30 mph; gusts to 75 mph
Expected snowfall: 1 to 3 in. 6 to 10 in. 4 to 8 in.
For above 10000 ft.
  Tuesday Tuesday Night Wednesday
Weather: Mostly cloudy with snow showers. Snow Level Below 7000' Mostly cloudy with snow showers. Snow Level Below 7000' Mostly cloudy with snow showers. Snow Level Below 7000'
Temperatures: 25 to 31 deg. F. 19 to 24 deg. F. 24 to 30 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 50 to 80 mph; gusts to 105 mph! 50 to 70 mph; gusts to 105 mph! 40 to 60 mph decreasing to 35 to 50 mph; gusts to 90 mph!
Expected snowfall: 1 to 3 in. 7 to 13 in. 7 to 10 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.