THIS AVALANCHE FORECAST EXPIRED ON May 2, 2020 @ 6:45 am
Avalanche Forecast published on May 1, 2020 @ 6:45 am
Issued by Steve Reynaud - Tahoe National Forest

A partial overnight refreeze of the snow surface is expected for this morning.  Loose wet avalanches and cornice fall will become possible as rapid warming occurs.  MODERATE avalanche danger will exist 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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Overnight temperatures, while still above freezing, were considerably cooler than previous nights.  These cooler temperatures along with radiational cooling from mostly clear skies should allow for a better overnight refreeze.  Rapid warming this morning with intense May sunshine will melt and break down the snow surface crust quickly providing a short window of supportable snow.  Loose wet avalanches will become possible as the snow surface becomes wet and unsupportive.  E-SE-S aspects will warm and melt the quickest this morning, followed by SW-W-NW-N-NE aspects

More and more exposed obstacles are present as our snowpack continues to melt out.  Avoid avalanche terrain as the snow becomes wet and deep.  Get an early start to catch the short window of supportable snow and finish before the snow deteriorates and becomes unsupportable.

 

 

Avalanche Problem 2: Cornice
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Cornice fall remains possible throughout the forecast region as rapid warming occurs today.  Large cornice blocks could cause injury or cornice fall could release loose wet or wet slab avalanches as they fall and load the slopes below.

Avoid areas and slopes below large cornices.  Stay well back from the edges of cornices along ridgelines and avoid any cracks that have developed along the backside of cornices. 

recent observations

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

Observations from Rubicon Peak (West Shore area) showed a weak overnight refreeze.  Snow conditions were mostly soft and punchy on all aspects.  Strong SW winds were keeping the ridges cool with firm snow, below that snow became soft and wet in the mid-morning.  Usable snow coverage began at 7300', which required a walk up the summer trail to access.

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

A slight cooling trend will continue through the weekend and into the beginning of next week.  Overnight temperatures, while still above freezing, have cooled into the mid to high 30's compared to the previous nights’ low to mid 40's along the Sierra Crest.  Sunny skies with increasing SW/W winds for this afternoon are expected.  Winds will continue to increase on Saturday and Sunday with the slight chance of thunderstorms for the northern portion of our forecast area.   

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
6am temperature: 33 to 39 deg. F.
Max. temperature: 42 to 52 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 15 to 30 mph
Maximum ridgetop wind gust: 56 mph
New snowfall: 0 inches
Total snow depth: 30 to 60 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Sunny. Snow levels 7500 feet increasing to 9000 feet in the afternoon. Chance of precipitation is 0%. Clear. Snow levels 8500 feet decreasing to 7500 feet after midnight. Chance of precipitation is 0%. Sunny then becoming partly cloudy. Snow levels 7500 feet increasing to 8500 feet in the afternoon. Chance of precipitation is 0%.
Temperatures: 55 to 61. deg. F. 32 to 37. deg. F. 52 to 58. deg. F.
Mid Slope Winds: Light winds becoming west around 15 mph with gusts to 35 mph in the afternoon. Southwest around 15 mph with gusts to 40 mph. Southwest 15 to 20 mph with gusts to 45 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Sunny. Snow levels 7500 feet increasing to 9000 feet in the afternoon. Chance of precipitation is 0%. Clear. Snow levels 9000 feet decreasing to 7500 feet after midnight. Chance of precipitation is 0%. Sunny then becoming partly cloudy. Snow levels 7500 feet increasing to 8500 feet in the afternoon. Chance of precipitation is 0%.
Temperatures: 49 to 55. deg. F. 29 to 34. deg. F. 46 to 52. deg. F.
Ridge Top Winds: West 15 to 20 mph. Gusts up to 40 mph decreasing to 30 mph in the afternoon. Southwest 15 to 20 mph. Gusts up to 30 mph increasing to 40 mph after midnight. Southwest 15 to 30 mph with gusts to 45 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