THIS SNOWPACK SUMMARY EXPIRED ON January 29, 2018 @ 8:57 am
Snowpack Summary published on January 27, 2018 @ 8:57 am
Issued by Ryan Lewthwaite -

bottom line:

WE ARE OPEN!!! The last storm has brought to our Bridgeport Winter Recreation Area just enough snow to open at 24". The Bridgeport Avalanche Center would like to welcome you to snowmobile in this beatiful place, but use discretion. The snowpack goes from deep pockets to bare ground in a very short space. Aspects ranging from North through East have the deepest wind deposits & also the most potential to avalanche. Sun baked Southern aspects & elevations below 8500' are thinest & are to be avoided. Please do not snowmobile through precious habitat such as: Sardine Meadows, Finley Meadows junction, & the Southside of Leavitt Lake. We encourage you to submit snowpack & avalanche observations to this website, & file permits electronically. Next Friday & Saturday we will be holding a Snowmobile specific Avalanche Awareness Clinic, please register if you are interested. Safe snowmobiling out there & we will see you on the snow!

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 with the arrival of our last precipitation have scattered our new snow & formed wind slabs. Some deposits were found to be 18" deep & primarily reside on Northeast to Eastern aspects at & above treeline. It is possible to trigger these wind slabs with the weight of a human, especially with their snowmobile, in & below avalanche terrain. Slopes above 35 degrees on these NE thru E aspects are deep & will present the most likely place to find propagating wind slabs.

Avalanche Character 2: Persistent Slab
Persistent Slab avalanches can be triggered days to weeks after the last storm. They often propagate across and beyond terrain features that would otherwise confine Wind and Storm Slab avalanches. In some cases they can be triggered remotely, from low-angle terrain or adjacent slopes. Give yourself a wide safety buffer to address the uncertainty.

Faceted weak layers still exist buried within the snowpack & will present trouble for travelers if found. The structure of our snowpack has continued to keep facet/crust combos since we have been putting out observations this season. Lately failure in these layers has been relatively unnoticeable but the possibility still remains that avalanches could occur at these interfaces. Our snowpack is thickest on North through East aspects at & above treeline & it is also where instabilities exist.

Avalanche Character 3: 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.

As the sun increases its intensity across mountain aspects look for loose wet avalanches to occur. Pay close attention to where the sun is relative to the slope you plan to ride. With temperatures rising for the next few days & freezing temperatures at night, look for places in the shade to find soft snow & avoid steep terrain traps that have been heated up. Loose wet avalanches like to start around warm objects or areas with abrupt terrain changes.

Snowpack Discussion

A new 6 to 10 inches fell on Wednesday night into Thursday & was heavily effected by the strong Southwest & West winds. Loading of new snow, as deep as 18", has formed wind slabs on leeward aspects that range from supportable to unsupportable as you travel. Above treeline on windward aspects, most or all of the new snow has been blown to deposits elsewhere. A persistent slab problem does still exist, although not nearly as reactive as earlier in the season. When we recieve rapid warm-up of temperatures & direct solar radiation expect loose wet avalanche activitey. If you travel today, & especially if it is your first ride of the season, dig around & get an understanding of the snowpack. Don't guess!

recent observations

Great splitboarding was had in the Virginia Lakes area on mellow terrain near treeline. Wind slabs were found to be soft & unsupportable on Northeast aspects. Half a dozen or more R1D1 loose dry avalanches occured mid-storm & were pretty minor.

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 25 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: mph
Maximum wind gust in the last 24 hours: mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 24 inches

Blocking High Pressure has entered our area & will remain for the next week or two.... No new snow to report. Temperatures will be in the mid thirtys today with below freezing temps at night. Minor clouds & partly sunny skies will dominate.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Saturday Saturday Night Sunday
Weather: Partly Cloudy Partly cloudy Partly cloudy with increasing sun
Temperatures: 39 - 47 deg. F. 21 - 29 deg. F. 47 - 53 deg. F.
Wind direction: West Light winds Light winds
Wind speed: 10 to 15 mph; gusts to 35 mph decreasing later Light winds; gusts to 25 mph Light winds
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Saturday Saturday Night Sunday
Weather: Partly cloudy Partly cloudy Partly cloudy with increasing sun
Temperatures: 33 - 38 deg. F. 22 - 27 deg. F. 39 - 44 deg. F.
Wind direction: Northwest Northeast Northeast
Wind speed: 15 to 25 mph; gusts to 40 mph decreasing to 30 mph later 15 to 20 mph; gusts to 30 mph 10 to 15 mph; gusts to 25 mph then decreasing
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.