THIS AVALANCHE FORECAST EXPIRED ON February 23, 2017 @ 6:48 am
Avalanche Forecast published on February 22, 2017 @ 6:48 am
Issued by Brandon Schwartz - Tahoe National Forest

Avalanche danger is CONSIDERABLE near treeline and above treeline. Avalanche danger is MODERATE below treeline. Wind slab and storm slab avalanche problems continue today. Backcountry travelers should not be surprised by human triggered avalanche activity at any elevation. Dangerous avalanche conditions exist in many areas. Cautious and conservative terrain decisions and route selection are warranted today. 9:50 am update to add Wet Loose avalanche problem.

 

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Near Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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Continued SW winds and another 6 to 12 inches of new snow last night will have further developed wind slabs in near treeline and above treeline terrain on NW-N-NE-E-SE-S aspects. These new wind slabs sit on top of recently unstable wind slabs that formed during this storm cycle. Avalanches that occur today could be large and destructive. Large potentially dangerous cornices exist in many ridgeline areas.

Use clues such as blowing snow, cornice formations, and wind pillows to help identify recently wind loaded slopes that may hold unstable wind slabs and should be avoided.

Avalanche Problem 2: Storm Slab
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New snow from last night was deposited under the coldest air temperatures of this storm cycle. Weak layers within the new snow may remain reactive today and allow for storm slab avalanche activity near treeline and below treeline on all aspects. The vast majority of any storm slab avalanche activity today will be human triggered.

Look for areas of snow surface cracking, especially while breaking trail and making fresh tracks either uphill or down. Avoid steep suspect slopes, especially in areas where snow surface cracking exists.

Avalanche Problem 3: Loose Wet
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9:50 am update - Cloud cover is significantly less than forecast. Loose wet avalanches are now possible on E-SE-S-SW-W aspects at all elevations. Avalanche size could range from small to large. Areas around rocks and trees will heat up quickly despite below freezing air temperatures. Avoid travel in areas where natural roll ball activity is occurring.
 

recent observations
Submit Observations

Observations made yesterday on Hidden Peak (West Shore Tahoe area) and well below treeline on Brockway summit found density changes within the recent storm snow. These density changes did not show propagating results in snowpit tests. On Hidden Peak around 8,600' in near treeline terrain as well as near the summit, wind effects became much more pronounced with skier triggered cracking of wind slabs from ski cuts and kicks.

Weather and CURRENT CONDITIONS
weather summary

The last wave of the departing storm system deposited another 6 to 14 inches of snow over the forecast area last night. Bands of convective snow showers linger this morning in the wake of the departing storm system. Off and on snow showers today could be high intensity for short periods of time. Additional new snow amounts around the forecast area today are expected to range from a trace to possibly 3 inches. Cold air has moved into the region behind the departing storm system with air temperatures in the teens this morning for most locations above 7,000'. Ridgetop winds out of the SW remain strong in speed this morning. Winds are forecast to gradually decrease to moderate in speed tonight. For tomorrow expect light snow showers and maximum daytime air temperatures in the 20s above 7,000'.

 

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 12 to 17 deg. F.
Max. temperature: 22 to 28 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 55 mph
Maximum ridgetop wind gust: 103 mph
New snowfall: 17 to 21 inches
Total snow depth: 155 to 190 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 skies. Snow showers decreasing as the day progresses. Mostly cloudy skies. Isolated snow showers through the night. Mostly cloudy skies. Scattered snow showers.
Temperatures: 23 to 28 deg. F. 6 to 12 deg. F. 22 to 27 deg. F.
Mid Slope Winds: W W W
Wind Speed: 15 to 25 mph with gusts to 45 mph. 15 to 20 mph with gusts to 35 mph. Light winds. Gusts to 25 mph in the morning.
Expected snowfall: Trace to 3 Up to 1 Up to 1
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy skies. Snow showers decreasing as the day progresses. Mostly cloudy skies. Isolated snow showers through the night. Mostly cloudy skies. Scattered snow showers.
Temperatures: 19 to 24 deg. F. 4 to 10 deg. F. 20 to 26 deg. F.
Ridge Top Winds: W W W
Wind Speed: 20 to 35 mph. Gusts to 75 mph decreasing to 60 mph in the afternoon. 20 to 30 mph with gusts to 60 mph, decreasing to 15 to 20 mph with gusts to 40 mph after midnight. 15 to 20 mph. Gusts to 45 mph decreasing to 30 mph in the afternoon.
Expected snowfall: Trace to 3 Up to 1 Up to 1
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