THIS SNOWPACK SUMMARY EXPIRED ON April 17, 2017 @ 11:48 am
Snowpack Summary published on April 14, 2017 @ 11:48 am
Issued by Ryan Lewthwaite -

bottom line:

Around a foot of new snow fell above 8000' with moderate winds. The storm entered our area warm & left cold, depositing snow on leeward aspects from the North through Southeast. We will see a two day period of clear skies before our next quick weather system moves into the BWRA with another flash of moisture. Pay close attention to new loose snow, wind slabs that have formed, cornice fall, & afternoon warm-up scenarios which may cause avalanches to occur.
Highway 108 is being actively plowed & snow-blown by Caltrans. The plowmen were working around the 8000' elevation sign & travel was slow & irregular in this area. Be patient & make contact with the operators before you proceed. There is mostly asphalt to the second parking area above the switchbacks at carbide corner, but be cautious. Closing Day is April 30th for the BWRA.

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.

Moderate winds from the South & West have transported new snow across the BWRA. Aspects facing North through Southeast have accumulated wind-driven snow & have formed tender slabs. These slabs carry the potential avalanche hazard of being easily triggered by human travel. The cohesion of a wind slab allows for failure propagation, which means effecting a small portion of a slab can cause the entire layer to avalanche.

Avalanche Character 2: 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.

New snow is effected very quickly & easily by the sun. Solar radiation will melt & loosen snow across a landscape, but not uniformly. Take into account the location of the sun in regard to the slopes you ride, especially later in the day. Slopes that get higher angle & more prolonged sun exposure will have the greatest influence & should be approached with higher caution.

Avalanche Character 3: Cornice
Cornice Fall avalanches are caused by a release of overhanging, wind drifted snow. Cornices form on lee and cross-loaded ridges, sub-ridges, and sharp convexities. They are easiest to trigger during periods of rapid growth from wind drifting, rapid warming, or during rain-on-snow events. Cornices may break farther back onto flatter areas than expected.

Wind-driven snow has beefed-up cornices all across the BWRA. Since this was the major contributing factor to the release of avalanches during our last storm cycle, id like to keep this component on peoples minds.

Snowpack Discussion

Around 1 foot of new snow fell during this recent storm. The storm came in warm & had a variety of precipitating snow forms including: stellars, graupel, & rimed particles. My pit was dug on a steep & wind sheltered area between Leavitt Creek & Road. We are working with a relatively "Right-Side-Up" snowpack which means; denser snow-grains are at the bottom & becoming less dense as you reach the surface. In most circumstances this means a more stable snowpack overall, but do not forget the variables & clues to pay attention to like new snow, wind loading & sun effects.

recent observations

Avalanche evidence was not easy to detect with the weather that we were having.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Friday Friday Night Saturday
Weather: Sunny then becoming partly cloudy Clear Sunny
Temperatures: 38-46 deg. F. 19-24 deg. F. 45-53 deg. F.
Wind direction: West NA South
Wind speed: Around 10 mph. Gusts up to 25 mph in the morning Light Light winds becoming south 10 to 15 mph with gusts to 25 mph in the afternoon
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Friday Friday Night Saturday
Weather: Sunny then becoming partly cloudy Clear Clear
Temperatures: 33-39 deg. F. 15-20 deg. F. 40-46 deg. F.
Wind direction: Southwest Southwest Southwest
Wind speed: 10 to 20 mph with gusts up to 45 mph in the morning 10 to 15 mph. Gusts up to 25 mph after midnight 10 to 15 mph. Gusts up to 35 mph in the afternoon
Expected snowfall: 0 in. 0 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.