THIS SNOWPACK SUMMARY EXPIRED ON February 22, 2017 @ 9:33 am
Snowpack Summary published on February 20, 2017 @ 9:33 am
Issued by Kyle Van Peursem - Bridgeport Avalanche Center

bottom line:

Dangerous avalanche conditions will exist at all elevations in the BWRA Monday and Tuesday due to very heavy snow and hurricane force winds.  Natural avalanches are likely and human triggered avalanches are certain due to large wind and storm slabs.  Travel in avalanche terrain is not recommended over the next two days.

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.

Very heavy snow and hurricane force winds from the SW will rapidly load NW-N-NE-E-SE facing slopes below, at, and above treeline.  Large and destructive natural avalanches, similiar to the ones we saw above Leavitt Lake during the last storm system, will be likely during this storm.  Avoid any and all wind loaded slopes and any slope that may be connected to a large avalanche path.  Stay away from all avalanche run out zones.

Avalanche Character 2: Storm Slab
Storm Slab avalanches release naturally during snow storms and can be triggered for a few days after a storm. They often release at or below the trigger point. They exist throughout the terrain. Avoid them by waiting for the storm snow to stabilize.

35-50" of snow is expected through Tuesday in the BWRA.  Flucuating snow levels will lead to mid-storm density changes and instabilities leading to likely natural and human triggered avalanches.  Snow levels are expected to rise to betwen 7500-8000 ft on Monday and will then lower through Tuesday which will lead to a mid-storm upside down snowpack.  Avoid all slopes steeper than 30 degrees today and stay away from avalanche run out zones. 

recent observations

A foot of medium density snow fell on Friday afternoon in the BWRA which settled out quickly.  There was a report of a snowmobile triggered avalanche above treeline, which broke 50'x50' from a wind slab that formed over a previously sun effected slope.  So far this morning, 8" of snow has fallen at both the Sonora Pass and Leavitt Lake SNOTELS, coming down at a rate of 1-2"/hr  


**The NWS has issued a winter storm warning for our area valid through 4pm Tuesday**

A very strong atmospheric river event wil impact our area Monday and Tuesday bringing very heavy snowfall with expected totals between 3-5 ft.  Lucikly, due to the higher elevation of the BWRA, snow levels will remain below our main forecast zone, peaking around 7500-8000 ft on Monday before falling Monday night.  Hurricane force SW winds are expected at near and above treeline Monday leading to whiteout conditions.  On Tuesday, snow and winds will begin to taper off by evening and temperatures will drop from the low 30's to teens.  Past Tuesday, flow will switch to the NW bringing much colder air and periods of low density snow showers mixed with periods of partly sunny skies.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Monday Monday Night Tuesday
Weather: Cloudy. Heavy Snow. Cloudy. Snow. Cloudy. Snow.
Temperatures: 36 to 42 deg. F. 27 to 33 deg. F. 30 to 38 deg. F.
Wind direction: Southwest South Southwest
Wind speed: 20 to 30 mph with gusts to 75 mph increasing to 30 to 45 mph with gusts to 85 mph in the afternoon. 30 to 50 mph with gusts to 85 mph. 30 to 45 mph with gusts to 80 mph.
Expected snowfall: 10 to 18 in. 8 to 14 in. 4 to 8 in.
For above 10000 ft.
  Monday Monday Night Tuesday
Weather: Cloudy. Heavy Snow Cloudy. Snow. Cloudy. Snow.
Temperatures: 29 to 35 deg. F. 20 to 26 deg. F. 23 to 31 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 50 to 70 mph with gusts to 120 mph 50 to 70 mph. Gusts up to 110 mph increasing to 120 mph after midnight 45 to 65 mph with gusts to 120 mph decreasing to 40 to 55 mph with gusts to 100 mph in the afternoon.
Expected snowfall: 12 to 20 in. 10 to 16 in. 4 to 8 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.