THIS AVALANCHE FORECAST EXPIRED ON April 30, 2020 @ 6:40 am
Avalanche Forecast published on April 29, 2020 @ 6:40 am
Issued by Brandon Schwartz - Tahoe National Forest

Last night's refreeze will be short lived this morning. Once the surface crust melts away, a loose wet avalanche problem will be present. Cornice fall remains an additional hazard. MODERATE avalanche danger exists today at all elevations. The last avalanche forecast for this season will post on 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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Air temperatures were even warmer and further above freezing last night than the night before. A weak snow surface refreeze driven from radiational cooling of the snowpack is expected to have occurred once again under mostly clear skies. The relatively thin and superficial melt-freeze surface crust formed overnight will melt rapidly today. The widow of supportable snow surface conditions will be short lived this morning. Once the surface crust melts away, residual deep wet snow below it will be exposed. This exposed deep wet snow will be prone to loose wet avalanches on all aspects and at all elevations. Avalanche size is expected at D1 to D2, depending on what the terrain is capable of producing.

Avalanche problems will develop quickest on E-SE-S aspects, with the other aspects not far behind today. This avalanche problem can be avoided by choosing not to travel in or below avalanche terrain once the surface crust has melted to the point that it is no longer supportable. Use aspect and slope angle to your advantage. Winds may briefly slow melt rates near ridgetops this morning, but expect rapid warming on the slopes below.

Avalanche Problem 2: Cornice
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Cornices that exist along many ridgelines will continue to collapse today. Large falling blocks of snow could injure a person on their own and may entrain more wet snow or trigger a loose wet avalanche when they impact the slope below.

Cornices frequently break farther back from their edge than expected. Cornices can also fail at unexpected times. Stay far back from the edges of cornices while on ridgetops and avoid travel underneath cornices.

recent observations
Submit Observations

* Spring melt-freeze conditions exist on all aspects across the forecast area. Meltwater drainage from the snowpack appears well established in many areas.

* Observations made yesterday on Incline Peak (Mount Rose area) and Pyramid Peak (Desolation Wilderness area) reported a weak to decent snow surface refreeze from the night before. The surface crust formed from this overnight refreeze melted away very quickly yesterday morning on all aspects.

* Large chunks of cornice fall continue to occur from the locations where large cornices exist.

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

Weather and CURRENT CONDITIONS
weather summary

Air temperatures were very warm again last night at all elevations and will approach record highs today. A weather disturbance passing to the north of the forecast area will increase cloud cover and ridgetop winds today. Mid to high level cloud cover is expected to begin increasing this morning and may not appreciably slow daytime warming. Ridgetop winds out of the SW are already increasing this morning. Wind speeds are forecast to peak tonight and continue through tomorrow. Cooler, much closer to average air temperatures are forecast for both tonight and tomorrow.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 48 to 53 deg. F.
Max. temperature: 62 to 70 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 11 mph
Maximum ridgetop wind gust: 35 mph
New snowfall: 0 inches
Total snow depth: 36 to 64 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy. Snow levels 11500 feet. Chance of precipitation is 5%. Mostly cloudy then becoming partly cloudy. Snow levels 10500 feet. Chance of precipitation is 5%. Sunny. Snow levels 9500 feet. Chance of precipitation is 0%.
Temperatures: 65 to 70. deg. F. 37 to 42. deg. F. 56 to 62. deg. F.
Mid Slope Winds: Southwest 15 to 20 mph. Gusts up to 25 mph increasing to 40 mph in the afternoon. Southwest 15 to 20 mph. Gusts up to 45 mph decreasing to 25 mph after midnight. Southwest 15 to 25 mph. Gusts up to 30 mph increasing to 45 mph in the afternoon.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy. Snow levels 11500 feet. Chance of precipitation is 5%. Mostly cloudy then becoming partly cloudy. Snow levels 10500 feet. Chance of precipitation is 5%. Sunny. Snow levels 9500 feet. Chance of precipitation is 0%.
Temperatures: 58 to 64. deg. F. 34 to 39. deg. F. 46 to 54. deg. F.
Ridge Top Winds: Southwest 15 to 30 mph. Gusts up to 45 mph increasing to 60 mph in the afternoon. Southwest 20 to 35 mph with gusts to 65 mph. Southwest 15 to 30 mph with gusts to 45 mph increasing to west 25 to 40 mph with gusts to 55 mph in the afternoon.
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