THIS AVALANCHE FORECAST EXPIRED ON March 27, 2018 @ 6:50 am
Avalanche Forecast published on March 26, 2018 @ 6:50 am
Issued by Brandon Schwartz - Tahoe National Forest

MODERATE avalanche danger will exist at all elevations today due to a combination of loose wet and wind slab avalanche problems. The vast majority of any avalanche activity that occurs today is expected to be human triggered, but an isolated natural avalanche is not impossible today or tonight.

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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Rapid warming under sunny skies and intense late March levels of incoming solar radiation will create widespread areas of snow surface melt today. Loose wet avalanche problems are expected to become increasingly widespread today and tomorrow. Expect the vast majority of instability to occur on steep E-SE-S-SW-W aspects. Loose wet avalanches are possible at all elevations today. Avalanche size up to D2 is possible (large enough to bury or injure a person).

Identify and avoid steep slopes where natural or human triggered roller balls are occurring.

Avalanche Problem 2: Wind Slab
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Lingering wind slabs left over from the past few days that formed under SW wind conditions will continue to present an avalanche problem in near treeline and above treeline areas today. Increasing NE winds today and tonight will redistribute snow on the ground creating new wind slabs. With this in mind, unstable wind slabs could exist on any aspect over the next 24 hours in near treeline and above treeline terrain. Avalanche size up to D2 is possible (large enough to bury or injure a person).

Identify areas of concern by looking for signs of wind drifted snow both past and present. Recent wind slab avalanches, blowing snow, cornice formations, wind pillow deposits, snow surface texturing, and snow surface cracking can all be used to identify areas of potentially unstable wind slab. If in doubt, avoid avalanche terrain in areas where signs of potential wind slab instability are present.

Forecast discussion

To the best of SAC's knowledge, triggering a deep slab avalanche has become very unlikely. For this reason it is no longer included as a specific avalanche problem. If you have unreported information relating to signs of deep slab instability occurring March 23 through the present, please submit an observation.

recent observations
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* At least one and possibly two skier/snowboarder triggered wind slab avalanches occurred yesterday on E to SE aspect terrain near the top of Jakes Peak (West Shore Tahoe area). A report was received of a human triggered avalanche that was large enough to bury a person and a second report was received of a smaller wind slab avalanche that was most likely human triggered.

* Other observations from around the West Shore Tahoe, Pole Creek, and Donner Summit areas reported wind slabs near and above treeline with varying degrees of triggering sensitivity ranging from reactive to unreactive.

* Large cornices exist in numerous ridgetop areas and may present a hazard to backcountry travelers.

* No signs of instability were reported yesterday from below treeline terrain in the West Shore Tahoe, Pole Creek, and Donner Summit areas.

* Numerous crowns from deep slab avalanche activity occurring during the March 20 - 22 storm cycle exist on N-NE-E aspects both above and below treeline in the 7,000' to 10,000' elevation range. No reports of post storm deep slab avalanches have been received.

Weather and CURRENT CONDITIONS
weather summary

High pressure is building over the forecast area bringing sunny skies. A warming trend will occur this week with above average air temperatures beginning on Wednesday. Ridgetop winds shifted from the SW to NE yesterday evening and are moderate in speed this morning. A strong NE wind event is expected to occur tonight.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 13 to 17 deg. F.
Max. temperature: 23 to 32 deg. F.
Average ridgetop wind direction: SW shifting to NE
Average ridgetop wind speed: 21 mph
Maximum ridgetop wind gust: 39 mph
New snowfall: Trace to 1 inches
Total snow depth: 84 to 118 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Monday Monday Night Tuesday
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 31 to 36 deg. F. 18 to 23 deg. F. 42 to 47 deg. F.
Mid Slope Winds: NE E E
Wind Speed: Around 10 mph in the morning, increasing to 10 to 15 mph with gusts to 25 mph in the afternoon. 10 to 15 mph with gusts to 30 mph. 10 to 15 mph with gusts to 25 mph in the morning, decreasing to around 10 mph.
Expected snowfall: 0 0 0
For 8000 ft. to 9000 ft.
Monday Monday Night Tuesday
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 26 to 32 deg. F. 17 to 22 deg. F. 37 to 43 deg. F.
Ridge Top Winds: NE NE E
Wind Speed: 10 to 20 mph with gusts to 30 mph. 15 to 25 mph with gusts to 40 mph, increasing to 25 to 35 mph with gusts to 75 mph after midnight. 20 to 30 mph with gusts to 55 mph.
Expected snowfall: 0 0 0
Disclaimer

This avalanche advisory is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This advisory 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 advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258