THIS SNOWPACK SUMMARY EXPIRED ON March 15, 2018 @ 11:13 am
Snowpack Summary published on March 13, 2018 @ 11:13 am
Issued by Ryan Lewthwaite -

bottom line:

Todays weather is variable, with lower elevation rain & strong winds & snow in the alpine. The arrival of 2' of new snow & another storm right behind that will elevate the avalanche hazard for the next week. This summary takes in to account the upcoming weather systems & urges recreationists to travel in areas of low consequence. If you see something in the backcountry related to snow & avalanches, we would really appreciate you submitting an observation to this site.

Avalanche Character 1: Wet Slab
Wet Slab avalanches occur when there is liquid water in the snowpack, and can release during the first few days of a warming period. Travel early in the day and avoid avalanche terrain when you see pinwheels, roller balls, loose wet avalanches, or during rain-on-snow events.

Since we have already seen plenty of small loose wet releases this week & a wet slab is potentially more destructive, lets worry first about the wet slab problem. As old wind & storm slabs soak in rain today they will be vulnerable to shearing at thin locations & abrupt changes in slope. Any additional weight added to already soft & melting slopes should have you concerned about the failures above you or triggering these from below. Rain is forecasted today below 8500' & will change to snow as this storm develops later today.

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.

We are back into winter again with up to 2' of new possible. Heavy mountain snow will collect on slopes that may be weakened by rain or that could have perfect crusty bed surfaces for sliding. Strong winds will aid in the transport of storm snow.

Avalanche Character 3: 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.

As winds shift from South to Southwest today expect loading to occur on North through Northeast aspects. Gusts are likely to reach 75 mph in the alpine creating touchy winds slabs tomorrow. Blowing snow will effect your ability to see & therefore our decision making skills will be altered.

Snowpack Discussion

After a warm week the new snow from last weekend has lingered in the trees & on North aspects but has significantly melted everywhere else. Loose wet indicators have been seen lately with one wet slab avalanching in good ski terrain. Wind drifts near & above treeline are measuring 100" while overall coverage is around 45". The top 4" of the pack has undergone several diurnal melt & refreeze cycles & rain will effect slopes below 8500' today. The storm we are anticipating will increase avalanche danger beyond the weekend & into next week.

recent observations

Since we reopened the BWRA over a week ago there has been a lot of activity. We have seen good numbers of snowmobilers & undergone a diverse avalanche cycle. The avalanche hazard has involved a variety of avalanche problems including: storm slab, wind slab, loose dry, loose wet, wet slab & cornice fall. Although benign, there is still a small chance we could see a deep slab instability as the storm intensifies. Please send us any snow observations that you encounter, we need your input! There are only two of us Rangers out there keeping you informed & open to snowmobiling. Be nice, abide the rules, & stay safe; we're here to help you!

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 39 deg. F.
Max. temperature in the last 24 hours: 45 deg. F.
Average wind direction during the last 24 hours:
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: 43 inches

We are on the threshold of another large winter storm entering our area today. Starting off as rain below 8500' this afternoon we will see a wind shift to the SW & cooling temps into the evening. A possible storm slab accumulation of 2' new snow by the end of tomorrow, with another storm at its back through Sunday. Winds will be howling from the S & SW creating large wind slabs on N through NE aspects.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Tuesday Tuesday Night Wednesday
Weather: Increasing clouds as a front approaches. Rain below 8500' with temps dropping later this afternoon turning to snow. Cloudy with rain changing into snow. Cloudy with snow
Temperatures: 37 - 45 deg. F. 20 - 26 deg. F. 27 - 35 deg. F.
Wind direction: South South shifting to Southwest Southwest
Wind speed: 15 to 25 mph; gusts to 60 mph 20 to 30 mph; gusts to 55 mph shifting to the Southwest 15 to 20 mph; gusts to 45 mph 10 to 15 mph; gusts to 40 mph
Expected snowfall: 1 to 5 in. 6 to 12 in. 2 to 6 in.
For above 10000 ft.
  Tuesday Tuesday Night Wednesday
Weather: Cloudy with snow. Cloudy with snow. Cloudy with snow.
Temperatures: 30 - 35 deg. F. 13 - 18 deg. F. 20 - 26 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 30 to 45 mph; gusts to 75 mph 30 to 45 mph; gusts to 70 mph 20 to 35 mph; gusts to 60 mph decreasing to gusts of 40 mph in the afternoon
Expected snowfall: 2 to 6 in. 8 to 14 in. 2 to 6 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.