THIS SNOWPACK SUMMARY EXPIRED ON April 18, 2018 @ 7:22 am
Snowpack Summary published on April 16, 2018 @ 7:22 am
Issued by Ryan Lewthwaite -

bottom line:

Snow has returned to the BWRA in it's usual blustery fashion. Extreme Southwest winds & accumulations of up to 16" of new snow will increase the avalanche activity for the next few days. Expect Storm & Wind formed slabs to be plentiful & sensitive on aspects NW-N-NE-E. Late season complacency from anyone you are riding with should be addressed in your pre-trip preparation. Snow has covered objects & streams that have been melting out recently, keep an elevated awareness & make situations known to those in your group. We have closed Sardine Meadows due to opening streams & critical habitat protection.

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.

Extreme winds from yesterday & this morning have created thick pockets of Wind slabs on leeward aspects. The swirling Southwest winds have formed tender slabs on slopes facing NW-N-NE-E. Cornices will help indicate where likely slabs exist & should be considered high consequence areas. Remember that triggering a slab remotely could propagate an avalanche far above you possibly effecting your whole riding contingent.

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.

Remote weather stations are showing 10-16" of accumulation, probably with the winds help, at a rate of 2" per hour. Heavily influenced by gale force winds, most of the storm slab potential will be located near & below treeline. The new snow will have the recent melt-freeze crust acting as a good bed surface for avalanches. Dig into & ride low consequence test slopes to gather info about your chosen riding zone.

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.

This avalanche problem will be directly related to how much the clouds lift. Today this issue will be possible & tomorrow (Tuesday) it shall quickly become very likely with the abundant sunshine.

Snowpack Discussion

Spring was ousted last evening as winter plunged itself back into fruition. Freezing temperatures & wind driven snows have accumulated on leeward aspects NW-N-NE-E. Wind slabs could be very deep in association with the gale force winds from the Southwest. Storm slabs will be thick & avoidance will be key today as things settle. If skies clear the likelihood of Loose Wet activity will be elevated. Expect the melt-freeze surface snow to be a supportable bed surface for avalanches to slide upon.

recent observations

No new avalanches to report for Sunday, although if skies clear today we will see activity. Moist & unfrozen snow surfaces were mostly unsupportable. Look today for Graupel that may have fallen with last nights storm. Consider Graupel within the new snow as a contributor to increased instability.

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 27 deg. F.
Max. temperature in the last 24 hours: 45 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: 10 inches
Total snow depth: 54 inches
weather

Yesterday we saw strong SW winds & 6.6C degrees (44F). No refreeze Saturday evening left moist & unsupportable snow surfaces. Sunday evening brought cold temps, snow, & of course gale force winds from the SW. Local Snotels are reporting between 10-16" of new snow at 6AM with 27F degrees (-2.8C).

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Monday Monday Night Tuesday
Weather: Cloudy with snow showers. Snow level below 7K' Mostly cloudy with scattered snow showers. Snow level below 7K' Sunny
Temperatures: 24 to 32 deg. F. 11 to 17 deg. F. 34 to 42 deg. F.
Wind direction: Southwest West Light winds
Wind speed: 15 to 25 mph; gusts to 50 mph decreasing to 35 mph later 10 to 15 mph; gusts to 30 mph Light winds
Expected snowfall: 2 to 4 in. 2 in. 0 in.
For above 10000 ft.
  Monday Monday Night Tuesday
Weather: Cloudy with snow showers. Snow level below 7K' Mostly cloudy with snow showers decreasing late. Snow level below 7K' Sunny
Temperatures: 16 to 23 deg. F. 6 to 11 deg. F. 28 to 33 deg. F.
Wind direction: Southwest West Northwest
Wind speed: 30 to 40 mph; gusts to 75 mph decreasing to 15 to 25 mph; gusts to 45 mph later 15 to 20 mph; gusts to 30 mph 10 to 15 mph early then becoming light
Expected snowfall: 2 to 5 in. 2 in. 0 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.