THIS SNOWPACK SUMMARY EXPIRED ON April 6, 2019 @ 8:01 am
Snowpack Summary published on April 4, 2019 @ 8:01 am
Issued by Ryan Lewthwaite -

bottom line:

Spring is upon us with warm quick storms bringing low elevation rain & wet snow accumulations around 8000'. Overnight warm temperatures with wet precipitation contrasted by periods of abundant sun, is a good recipe for Loose Wet avalanches.

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.

Several larger sized Loose Wet avalanches were observed yesterday with the newly deposited 4-6" of snow. Wind transported snow on NW-SE aspects gained sun immediately after the warm storm causing degradation of the surface snow & the Loose Wet activity that was seen. Overnight temperatures were just below freezing allowing for a long period of melting which can add to the Loose Wet avalanche problem.

Snowpack Discussion

A quick moving blast of precipitation over our area dropped 4-6" of wet snow, rain, & graupel. Southwest winds of moderate intensity transported the new snow to  shallow Wind Slabs on aspects which face NW-SE. Sun & above freezing temperatures immediately following the snowfall allowed for rapid melting of the new snow causing several D2 Loose Wet avalanches. The primary instability will be the newly deposited surface snow & any additional accumulations we gain. Rain on snow is likely in the next few days adding to the Loose Wet avalanche problem.

recent observations

4/3~ 4-6" HN24 with rapid melting causing several larger sized D2 Loose Wet avalanches. Wind Slabs have formed on NW-SE aspects above treeline.

4/1~ Loose Wet avalanche activity, small in size. Skiier & snowmobile triggering likely on aspects gaining intense sun.

3/30~ Loose Wet activity minor, good stability for snowpack. Rockfall on Hwy 108. 

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 30 deg. F.
Max. temperature in the last 24 hours: 44 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: Moderate mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 98 inches
weather

March has us enduring warm wet storms with modest snow accumulations in the higher elevations. Today a weak low pressure system will bring rain to elevations around 7500-8000' with wet snow showers above that. A succession of quick low intensity storms is on the horizon for the next few days with minor showers & moderate winds from the Southwest. Expect sun to rapidly degrade any new snow that it shines upon. Temperatures will fluctuate with 20F degrees swings at night allowing for superficial refreezing overnight.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Thursday Thursday Night Friday
Weather: Mostly cloudy with isolated showers in the afternoon. Snow Level Around 7500' Mostly cloudy with scattered snow showers. Snow Level 7000' Mostly cloudy with scattered snow showers. Snow Level 7000'
Temperatures: 36 to 46 deg. F. 23 to 28 deg. F. 32 to 42 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 15 mph; gusts to 25 mph 15 mph; gusts to 30 mph 15 to 25 mph; gusts to 40 mph
Expected snowfall: trace in. 1 in. 2 in.
For above 10000 ft.
  Thursday Thursday Night Friday
Weather: Mostly cloudy with isolated showers in the afternoon. Snow Level Around 7500' Mostly cloudy with scattered snow showers. Snow Level 7000' Mostly cloudy with scattered snow showers. Snow Level 7000'
Temperatures: 26 to 34 deg. F. 17 to 22 deg. F. 23 to 31 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 15 to 20 mph; gusts to 30 mph 15 to 25 mph; gusts to 35 mph 15 to 30 mph; gusts to 50 mph
Expected snowfall: trace in. 1 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.