THIS SNOWPACK SUMMARY EXPIRED ON February 19, 2017 @ 9:00 pm
Snowpack Summary published on February 17, 2017 @ 9:00 am
Issued by Kyle Van Peursem - Bridgeport Avalanche Center

bottom line:

Friday - Saturday:  Avalanche danger in the BWRA will be elevated with human triggered wind slab avalanches likely on wind loaded slopes steeper than 35 degrees.  Due to the unusual wind direction (SE), wind slabs may exist in atypical locations.

Sunday:  The avalanche danger will subside during a break between storms but human triggered wind slab avalanches will still be possible on wind loaded slopes steeper than 35 degrees

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 will accompany moderate snowfall amounts as a storm system moves through our area Friday through Saturday morning.  Strong south/southeast winds with gusts expected between 50-60 mph will easily load W-NW-N-NE facing slopes and produce sensitive wind slabs and cornices on unsual slopes that will be easily triggered by a snowmobiler.  It is recommended to stay off of wind loaded slopes steeper than 35 degrees Friday through Saturday.  These instabilities will strengthen Sunday and will be less sensitive to human triggers, but will still be possible. 

Snowpack Discussion

A week of high pressure produced various aspect-dependent snow surfaces around the BWRA, inclduing surface hoar in sheltered meadows, sun/melt-freeze crusts on southerly aspects, developing near-surface facets on shaded upper-elevation northerly facing slopes, and wind boards on exposed upper-elevation leeward slopes.  Luckily, a quick moving storm on Thursday dropped 1-2" of wet snow which, in a sense, 'equalized' the snow surface on all aspects.  New snow today and tomorrow should bond quickly to this wet snow, minimizing new snow instabilities.  Wind slabs issues will be the biggest avalanche concern this weekend. 

recent observations

Observations from the Koenig/Latopie Lakes and the PCT crossing area on Wednesday showed a generally stable snowpack with no signs of recent avalanche activity, though SW winds were beginning to pick up and load northerly facing slopes.  On Thursday, Ryan was up in the BWRA and found 1-2" of wet new snow with strong winds on the most exposed ridgelines.

weather

**The National Weather Service has issued a winter weather advisory valid Friday through 10 am PST Saturday**

We are in store for another round of atmospheric river events over the next 5-days.  The first storm will impact our area Friday through Saturday morning, with 10-20" of medium density snow expected accompanied by strong winds up to 60 mph in the most exposed locations.  We will get a break Saturday afternoon through Sunday afternoon before a stronger storm moves in Sunday night.  Right now, this storm is expected to be warmer with freezing levels around 8000 ft and will be accompanied by hurricane force winds and very heavy precipitation.  Another storm slides in right behind it on Tuesday night.  Precipitation totals Sunday night through Wednesday are expected to be around 50" snow/5.5" water which will bring our 5-day storm total (Friday-Wednesday) to 60-70" snow/6-9" water.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Friday Friday Night Saturday
Weather: Cloudy. Snow. Cloudy. Snow. Cloudy. Snow likely in the morning, then chance of snow showers in the afternoon.
Temperatures: 28 to 33. deg. F. 21 to 26. deg. F. 30 to 36. deg. F.
Wind direction: South Southeast Southwest
Wind speed: 15 to 25 mph. Gusts up to 30 mph increasing to 45 mph in the afternoon. 15 to 25 mph. Gusts up to 45 mph. Light winds. Gusts up to 30 mph in the morning.
Expected snowfall: 3-9 in. 2-7 in. 1-2 in.
For above 10000 ft.
  Friday Friday Night Saturday
Weather: Cloudy. Snow. Cloudy. Snow. Cloudy. Snow likely in the morning, then chance of snow showers in the afternoon.
Temperatures: 22-28 deg. F. 16 to 22 deg. F. 23 to 29 deg. F.
Wind direction: South South South
Wind speed: 20 to 30 mph. Gusts up to 45 mph increasing to 60 mph in the afternoon. 20 to 35 mph with gusts to 60 mph. 10 to 15 mph. Gusts up to 40 mph decreasing to 30 mph in the afternoon.
Expected snowfall: 5-10 in. 3-8 in. 1-2 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.