Snowpack Summary published on April 14, 2018 @ 8:07 am
Issued by Ryan Lewthwaite -

bottom line:

A quick refresh of the snow surface on Thursday evening gave us around 3-5" new. Afternoon rapid melting will increase the Loose Wet avalanche potential, especially these new accumulations. Tomorrow afternoon the winds will increase as we receive another fast moving low pressure system. The arrival will be wet & rainy with a cold-smoke finish, possibly seeing another 6-8" by Tuesday morning. Caltrans has been working hard with plowing progression to within one quarter mile from Sonora Pass. Roadside canyon walls are solid & precarious.

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.

Small Loose wet avalanche activity can be expected in the warmer afternoon hours. Direct sunlight & teperatures near 50F degrees will melt & decrease viscosity of the surface snow. The quick storm on Thursday that deposited 3-5" sits atop a solid melt-freeze crust & is where the most activity is likely to occur. 

Snowpack Discussion

We are transitioning to spring corn with intermittent snow squalls refreshing the snows surface. Conditions are highly variable with supportable to icy mornings & hightened afternoon Loose Wet potential. Melt-freeze crusts are 2-3cm thick on the surface but inversions during the evening could make these crusts weaker than expected. Although the clear skies will help keep the snow solid this dynamic could produce near-surface facets that decompose with afternoon warming. Test slopes can help you better understand what the conditions are like before you commit to the bigger climbs.

recent observations

Yesterday (Friday) saw warm temperatures but a supportable crust lingered long into the afternoon. The 3-5" of snow that accumulated late Thursday was blown off ridgetops & has settled near treeline. Wind slabs that formed were small, evenly distributed & cooked by the sun. Although relatively benign, these slabs may be tender & somewhat reactive in some isolated areas. Near ridgetops & above treeline areas the surface is icy & should be treated with caution. The streams have melted out significantly, making access to many areas challenging. 

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 32 deg. F.
Max. temperature in the last 24 hours: 45 deg. F.
Average wind direction during the last 24 hours:
Average wind speed during the last 24 hours: mph
Maximum wind gust in the last 24 hours: mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 46 inches

An especially nice day on-tap today with sun & warm temperatures. Winds will be light & from the Southwest. A low pressure system is forecasted to enter our region Sunday with increased winds & precipitation. A WIND ADVISORY has been put into effect from 2PM Sunday to 2AM Monday. The earliest precip may come in the form of rain but will change to snow as temps drop into the teens by Sunday evening. Accumulations seem to favor the Tahoe basin but we could see around 6-8" of new snow before Tuesday morning. In the BWRA last evening we experienced another temperature inversion with Sonora Snotel at 32F degrees & Leavitt Snotel at 34F degrees.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Saturday Saturday Night Sunday
Weather: Sunny Partly cloudy then becoming mostly cloudy. Partly cloudy.
Temperatures: 49 to 57 deg. F. 29 to 34 deg. F. 44 to 54 deg. F.
Wind direction: Light winds Southwest Southwest
Wind speed: Light winds 10 to 15 mph; gusts to 25 mph increasing to 40 mph late. 15 to 20 mph; gusts to 45 mph increasing to 20 to 30 mph; gusts to 60 mph later.
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Saturday Saturday Night Sunday
Weather: Sunny Partly cloudy then becoming mostly cloudy. Mostly cloudy then becoming partly cloudy.
Temperatures: 44 to 50 deg. F. 24 to 29 deg. F. 36 to 44 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 10 to 15 mph 15 to 25 mph; gusts to 30 mph increasing to 45 mph late. 25 to 35 mph increasing to 30 to 45 mph later; gusts to 65 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.