THIS SNOWPACK SUMMARY EXPIRED ON March 4, 2019 @ 5:31 am
Snowpack Summary published on March 2, 2019 @ 5:31 am
Issued by Ryan Lewthwaite -

bottom line:

The incoming storm will bring with it a mix of rain & snow for below treeline areas around 7500'. In the alpine, prevailing winds from the Southwest will be Strong enough to strip dry snow & collect it in places near & below treeline forming Wind Slabs. Lower elevation & transition zones could produce small Loose Wet avalanches on all aspects. Keep your terrain simple & listen for possible thunder.

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 winds from the Southwest will strip most of the alpine snow & redeposit it to near & below treeline areas. Look for areas where winds slow down or change direction as they will likely tell you where Wind Slabs could potentially reside. Use cautious terrain management techniques when traveling in areas of consequence & ride with a skilled partner who has the proper equipment.

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.

Rain & even thunderstorms could visit the BWRA this weekend. A warming trend could create Loose Wet avalaches to areas below 8000', & if enough rains persist be mindful of Wet Slab avalanches. Signs of the Loose Wet avalanche problem include pinwheels & a lumpy surface texture of the snow.

Snowpack Discussion

Winds have been a factor lately, redistributing any snow that is not locked up to Lee aspects. Small snow accumulations have been moved to near & below treeline areas on top of an already robust snowpack. Warm temperatures & increasingly more direct March sun has effected the surface of the snowpack, forming crusts on exposed slopes. The snowpack has been spatially variable, with several small to medium (D1 to D2) wind slab avalanches in areas of higher frequency of occurance. A crust layer exists 35 cm down from the surface with a softer layer below it, but have been unreactive in stability tests.

recent observations

-Wind transported snow has been the common theme. Wind Slabs have developed in cross-loaded terrain features near treeline causing D2 avalanches. The "Repeat Offender" slid to just above Leavitt Lake Road.

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 31 deg. F.
Max. temperature in the last 24 hours: 36 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: Moderate mph
Maximum wind gust in the last 24 hours: Strong mph
New snowfall in the last 24 hours: 1 inches
Total snow depth: 94 inches
weather

Today a fast moving Pacific storm will create a mix of rain & snow. The Sierra Crest may see over a foot of new heavy snow, while lower valleys will have wetting rains. The expected winds from the Southwest will be moderate with gusts to strong. Any dry snow will be transported across the mountains or held in suspension. Areas of regular deposition could see drifts up to 5 times the amount of the expected snowfall totals. There is a possibility of thunderstorms associated with Sundays lingering rain & snow showers. Next week will be active & variable with another Atmospheric River slated for our zone. Predicted even warmer, this AR could produce severe winds & very dangerous avalanche conditions.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Saturday Saturday Night Sunday
Weather: Mostly cloudy with snow showers & possibly rain in some lower elevation areas. Snow Level 7000' Partly to mostly cloudy with a chance for snow showers. Snow Level 7000' Mostly cloudy with snow showers & possibly rain in some lower elevation areas. A slight chance of thunderstorms in the afternoon. Snow Level Below 7000'
Temperatures: 31 to 39 deg. F. 23 to 28 deg. F. 31 to 39 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 15 to 30 mph; gusts to 70 mph in the afternoon 15 to 30 mph; gusts to 75 mph 15 to 20 mph, gusts to 60 mph
Expected snowfall: 5 to 11 in. 2 in. 2 in.
For above 10000 ft.
  Saturday Saturday Night Sunday
Weather: Cloudy with snow showers. Snow Level 7500' Mostly cloudy with a chance for snow showers. Snow Level 7000' Mostly cloudy with a chance for snow showers. Snow Level Below 7000'
Temperatures: 23 to 29 deg. F. 18 to 23 deg. F. 31 to 39 deg. F.
Wind direction: South shifting Southwest Southwest Southwest
Wind speed: 25 to 35 mph increasing to 30 to 45 mph in the afternoon; gusts to 65 mph 30 to 45 mph; gusts to 70 mph 30 to 45 mph decreasing to 25 to 35 mph in the afternoon; gusts to 65 mph
Expected snowfall: 9 to 14 in. 2 in. 2 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.