THIS AVALANCHE ADVISORY EXPIRED ON March 7, 2017 @ 6:50 am
Avalanche Advisory published on March 6, 2017 @ 6:50 am
Issued by Steve Reynaud - Tahoe National Forest

Considerable avalanche danger will continue today due to additional snow and strong to gale force winds.  Dangerous avalanche conditions exist.  Wind slab, storm slab, and loose dry avalanche problems are likely at all elevations.  Natural avalanches are possible and human triggered avalanches are likely.  Evaluate snow and terrain carefully before committing to a slope.

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.

3. Considerable

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Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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Strong to gale force SW/W winds with additional snow today will further wind slab development on NW-N-NE-E-SE-S aspects in near and above treeline terrain.  These wind slabs could be natural or human triggered and be well over 4 feet deep in size.  Avalanches associated with these wind slabs and/or large cornice failures could have severe consequences.

Avoid steep wind loaded terrain and run out zones.  Do not travel below large cornices.  Look for blowing snow, cornice formation, and wind pillows as clues to where wind slabs are located.  Make a plan to avoid all steep wind loaded areas. 

Avalanche Problem 2: Storm Slab
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Storm slabs will be likely on all aspects in near and below treeline terrain.  Storm snow totals are 2 to 3+ feet with additional snow forecasted for this morning.  Cold temperatures may slow the bonding process of this new storm snow.  Additional intense snowfall rates this morning may also add to instability.  Look for cracking around skis or any signs of cohesion of the new storm snow.  Avoid slopes that have signs of unstable snow.

Avalanche Problem 3: Loose Dry
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Continued cold temperatures with additional snow will make loose dry avalanches likely on slopes steeper than 35 degrees in wind protected areas.  Most loose dry avalanches will be in wind protected below treeline terrain but could also occur in other more exposed locations.  Terrain traps, such as rocks, trees, and gullies, would magnify the consequences of being caught in a small loose dry avalanche

recent observations

Observations were made and received from Hidden Peak (West Shore area), Powderhouse Peak (Luther Pass area), and Juniper Creek (Hirschdale area).  Signs of storm slab and wind slab instabilities were reported from all areas.  A small skier triggered storm slab was observed on Hidden Peak that was 1' deep at 7600' on a NE aspect.  All areas reported sensitive wind slabs with test slope failures.  Snowfall rates were observed up to 3-4''/hour in the morning before tapering and then picking back up in the afternoon.  Blowing snow with white out conditions occurred throughout most of the day.

Weather and CURRENT CONDITIONS
weather summary

Storm snow totals so far throughout our area are in the 2 to 3+ feet range above 7000'.  Snow showers will continue today and intensify this morning before tapering off later this afternoon.  Up to 3'' of additional snow forecasted for today with strong to gale force SW/W winds above 8000'.  Convective showers and lake effect snow could favor some areas more than others with additional snow like what occurred yesterday.  A warming trend begins on Tuesday/Wednesday and then chances for more storms over the weekend and into the following week. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 9 to 11 deg. F.
Max. temperature in the last 24 hours: 22 deg. F.
Average wind direction during the last 24 hours: SW/W
Average wind speed during the last 24 hours: 50 to 80 mph
Maximum wind gust in the last 24 hours: 105 mph
New snowfall in the last 24 hours: 12 to 20 inches
Total snow depth: 142 to 223 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Monday Monday Night Tuesday
Weather: Cloudy. Snow showers with blowing snow in the morning then scattered snow showers in the afternoon. Mostly cloudy. Isolated snow showers. Cloudy. Slight chance of snow showers.
Temperatures: 26 to 31 deg. F. 18 to 24 deg. F. 36 to 41 deg. F.
Wind Direction: SW SW SW
Wind Speed: 20 to 30mph with gusts to 50mph. 15 to 25mph with gusts to 45mph. 10 to 15mph with gusts to 30mph.
Expected snowfall: Up to 3 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Monday Monday Night Tuesday
Weather: Cloudy. Snow showers with blowing snow in the morning, then scattered snow showers in the afternoon. Mostly cloudy. Isolated snow showers. Mostly cloudy then becoming cloudy. Slight chance of snow showers.
Temperatures: 23 to 28 deg. F. 18 to 23 deg. F. 35 to 40 deg. F.
Wind Direction: W W shifting to SW SW
Wind Speed: 30 to 45mph with gusts to 90mph. 30 to 40mph with gusts to 80mph shifting to the SW 20 to 35mph with gusts to 75mph after midnight. 20 to 30mph with gusts to 60mph.
Expected snowfall: Up to 3 in. 0 in. 0 in.
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