THIS SNOWPACK SUMMARY EXPIRED ON January 2, 2018 @ 10:57 am
Snowpack Summary published on December 31, 2017 @ 10:57 am
Issued by Ryan Lewthwaite -

bottom line:

We are still sadly CLOSED for the season... If thin coverage & summerlike weather is eating away at your mental state, keep sane by joining us for an Avalanche Awareness Class on January 19th & 20th. We are out there daily, traveling by foot, trying to make it snow & keeping you informed. Currently a Normal Caution prevails due to a lack of riding product. Although, within our snowpack structure two areas of concern are noticed to have avalanche potential. Please refrain from "poaching" the winter rec area, we have stealthy Forest Protection Officers on patrol continuously, who will issue citations.

Avalanche Character 1: Normal Caution
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Use normal caution when travelling in the backcountry.

I wish there were more to report on but it has been hot & dry @ the BWRA. We are still CLOSED for the season. This is a great time to get the skills & equipment ready for when the skies open up & snowmobiling begins.

Avalanche Character 2: 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.

Although the snowpack does not exist in much of our recreation area, where it has been wind deposited it is dicey. Snow depths vary from -1cm to 130cm (0.4" - 51") in the most extreme loaded areas. The most recent quick precipitation we received over a week ago has formed a denser wind slab which sits upon facetted grains. These grains below the wind slab have poor cohesion & large air spaces which can help promote avalanches if triggered. The deepest wind deposits are on North through Eastern aspects above 8500'.

Avalanche Character 3: 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.

A layer buried within the snowpack that might become a season-long avalanche hazard exists from the storm that happened around Thanksgiving. Following that event a prolonged period of warm & dry weather persisted, deteriorating what snow was available. In isolated areas (about 1/3 up from ground within snowpack) a crust has formed with faceting on either side of this layer creating a poor structure. Although not consistently dispersed & reactive this layer of concern could linger as we get more precipitation this winter.

Snowpack Discussion

Our snowpack is thin & in a state of deterioration from warm temperatures & no new precipitation. The isolated areas where a snowpack exists are located mainly on North through East aspects above 8500'. Changes in snowpack structure vary greatly across the landscape, even within a few feet of where snow profiles are dug. That being considered, overall we are seeing two layers of possible concern. The uppermost recent snow has formed a variable wind slab sitting on facets. Also, a persistent slab problem may exist around the snow that fell at Thanksgiving.

recent observations

An old slab avalanche that has become more pronounced exists above the motorized PCT crossing @ Sonora Pass. Upon investigation the wind slab likely slid upon our persistent slab crust. Winds have scoured, transported dirt, & blown in new snow erratically making it previously hard to see in the shadows


Unseasonably warm temperatures exist in the BWRA. Last evening it remained above freezing at our Snotel stations located at 9604'. The High Pressure ridge that has dominated our area will begin to break up Tuesday evening as a weak system moves in. So far these waves of moisture show low intensity & quick duration with snow levels climbing to 8000'.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Sunday Sunday Night Monday
Weather: Mostly Cloudy Mostly cloudy then becoming partly cloudy Partly cloudy
Temperatures: 45 - 53 deg. F. 26 - 34 deg. F. 46 - 54 deg. F.
Wind direction: Southwest Southwest Light winds
Wind speed: <10 mph <10 mph Light winds
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Sunday Sunday Night Monday
Weather: Mostly cloudy Mostly cloudy then becoming partly cloudy Partly cloudy
Temperatures: 37 - 43 deg. F. 27 - 32 deg. F. 39 - 45 deg. F.
Wind direction: Southwest Southwest West
Wind speed: 15 to 25 mph gusting 40 mph 10 to 20 mph 10 to 15 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.