Snowpack Summary published on April 18, 2019 @ 7:17 am
Issued by Ryan Lewthwaite -

bottom line:

Hot temperatures will have the snow melting quickly, which could bring about larger sized Loose Wet avalanches. As we start to lose a substantial refreeze overnight & terminal spring encroaches, conditions will rapidly deteriorate. Plowing on 108 has progressed to Rockslide Corner, near the 8000' mark. Virginia Lakes Rd is moving along much quicker & we may see an open road relatively soon. How you park in these transitioning road conditions is important for the flow of vital vehicles, use one lane only.

Avalanche Character 1: 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.

High pressure has us under warm sunny skies & temperatures above normal. Melting & the loosening of snow grains will become more rapid today with the possibility of larger sized Loose Wet avalanches. An overnight temperature inversion could allow more creeping of snow in the near & above treeline areas, especially if they gain prolonged sun exposure.

Snowpack Discussion

Yesterday a solid overnight refreeze allowed for perfect spring corn conditions well into the afternoon hours. Around 2" of new snow fell on Tuesday most of which was supercooled vapor in the form of rime. The new snow was cast to N-E Lee aspects in shallow unreactive wind slabs. The sun cooked out any loose dry snow available for transport. With hot temperatures today expect melting rates to increase. Small Loose Wet avalanches could grow bigger with ample melting. If your track digs deep into the Loose Wet snow grains that is a good indicator that steeper slopes could be unstable. 

recent observations

~4/17 At Virginia Lakes & Sonora great corn conditions were consistent across the hills. No new avalanches to report in the BWRAs.

~4/16 2" new snow above 8000'

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 30 deg. F.
Max. temperature in the last 24 hours: 51 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: Light mph
Maximum wind gust in the last 24 hours: Moderate mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 87 inches

Warmth & sunshine through tomorrow, with temperatures above normal. Winds this morning should decrease as we gain temperatures into the mid 50's for the higher elevations. Friday evening unstable air moves in with increasing clouds & very spotty precipitation. A low chance for isolated thunderstorms & even virga are possible with convective storm cells. A mild temperature inversion occurred overnight with Leavitt Snotel around 5F degrees warmer than Sonora.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Thursday Thursday Night Friday
Weather: Sunny. Clear. Sunny with increasing clouds.
Temperatures: 51 to 61 deg. F. 32 to 38 deg. F. 53 to 63 deg. F.
Wind direction: East Light winds Southwest
Wind speed: 10 to 15 mph; gusts to 30 mph then becoming light Light winds 10 to 20 mph; gusts to 35 mph later
Expected snowfall: 0 in. 0 in. 0 in.
For above 10000 ft.
  Thursday Thursday Night Friday
Weather: Sunny. Clear. Partly cloudy.
Temperatures: 44 to 52 deg. F. 27 to 32 deg. F. 45 to 53 deg. F.
Wind direction: Southeast Southwest Southwest
Wind speed: 15 to 20 mph; gusts to 35 mph 10 to 15 mph 15 to 25 mph; gusts to 35 mph
Expected snowfall: 0 in. 0 in. 0 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.