THIS AVALANCHE FORECAST EXPIRED ON May 1, 2020 @ 6:46 am
Avalanche Forecast published on April 30, 2020 @ 6:46 am
Issued by Steve Reynaud - Tahoe National Forest

A partial refreeze of the snow surface is expected this morning.  Loose wet avalanches will become possible as the snow surface melts and loses supportability.  Cornice fall will also be a concern.  MODERATE avalanche danger will exist today at all elevations.  The last avalanche forecast for the season will be on Sunday May 3rd.

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
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Above freezing overnight temperatures with mostly clear skies will allow the snow surface to partially refreeze due to radiational cooling.  As rapid warming occurs this morning, this surface crust will quickly melt and become unsupportive.  Loose wet avalanches will become possible as the snow becomes wet and deep.  E-SE-S aspects will warm and melt the quickest, followed by SW-W-NW-N-NE aspects as the day progresses.  Strong SW winds today may slow melt rates near ridgetops, but expect rapid warming on the slopes below.

Avoid avalanche terrain once the snow surface has become wet and unsupportive.  Exposed obstacles could pose travel concerns as our snowpack continues to melt out.  

Avalanche Problem 2: Cornice
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Cornice fall remains a concern throughout the forecast area.  Large cornice collapses could cause injury or trigger loose wet or wet slab avalanches as they load the slopes below.  Avoid traveling on slopes below large cornices.  Along ridges, these cornices can break much farther back from there edges than expected. 

recent observations
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Spring melt freeze conditions exist on all aspects and elevations across the forecast area.

Observations were conducted yesterday on Mt. Judah in the Donner Summit area.  A weak to non-existent refreeze was seen in this area with above freezing overnight temperatures along with cloudy skies.  Even with that, the snow surface was still mainly supportive for the morning hours.  Many obstacles exist as the snowpack melts out quickly at this location.

Numerous glide cracks exist were the snowpack overlies steep slabs of rock. No signs of glide avalanches have been reported.

Weather and CURRENT CONDITIONS
weather summary

Increasing winds with a gradual cooling trend will begin today as a low pressure system moves north of our area.  SW winds will increase with sunny skies expected.  Temperatures will begin to cool off from what we experienced on Tues/Wed and get down closer to seasonal norms.  Chances of thunderstorms over the weekend still remain north of our area.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 38 to 45 deg. F.
Max. temperature: 52 to 61 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 15 to 30 mph
Maximum ridgetop wind gust: 47 mph
New snowfall: 0 inches
Total snow depth: 32 to 62 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Thursday Thursday Night Friday
Weather: Sunny. Snow levels 9000 feet. Chance of precipitation is 0%. Clear. Snow levels 9000 feet decreasing to 7500 feet after midnight. Chance of precipitation is 0%. Sunny. Snow levels 7500 feet increasing to 8500 feet in the afternoon. Chance of precipitation is 0%.
Temperatures: 56 to 62. deg. F. 34 to 39. deg. F. 55 to 61. deg. F.
Mid Slope Winds: Southwest 15 to 25 mph. Gusts up to 30 mph increasing to 45 mph in the afternoon. Southwest 15 to 25 mph. Gusts up to 40 mph decreasing to 30 mph after midnight. Southwest around 15 mph with gusts to 30 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Thursday Thursday Night Friday
Weather: Sunny. Snow levels 9000 feet. Chance of precipitation is 0%. Clear. Snow levels 8500 feet. Chance of precipitation is 0%. Sunny. Snow levels 7500 feet increasing to 8500 feet in the afternoon. Chance of precipitation is 0%.
Temperatures: 50 to 56. deg. F. 31 to 36. deg. F. 49 to 55. deg. F.
Ridge Top Winds: Southwest 15 to 30 mph. Gusts up to 35 mph increasing to 45 mph in the afternoon. Southwest 15 to 30 mph. Gusts up to 45 mph decreasing to 35 mph after midnight. West 15 to 20 mph with gusts to 30 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
Disclaimer

This avalanche forecast is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This forecast covers the Central Sierra Nevada Mountains between Yuba Pass on the north and Ebbetts Pass on the south. Click here for a map of the forecast area. This forecast applies only to backcountry areas outside established ski area boundaries. This forecast describes general avalanche conditions and local variations always occur. This forecast expires 24 hours after the posted time unless otherwise noted. The information in this forecast is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the avalanche forecast call (530) 587-3558 x258