THIS AVALANCHE ADVISORY EXPIRED ON March 25, 2017 @ 6:45 am
Avalanche Advisory published on March 24, 2017 @ 6:45 am
Issued by Brandon Schwartz - Tahoe National Forest

Avalanche danger will increase to CONSIDERABLE today as a storm system moves through the forecast area. Wind slab and storm slab avalanche problems are expected today. Loose wet avalanche problems are also a possibility. A gradual increase in snowpack instability is expected this morning, transitioning to a rapid increase in snowpack instability this afternoon. Dangerous avalanche conditions will form today. Identify and avoid potentially unstable slopes.

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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New snow and wind will allow wind slabs to build throughout the day today with a period of rapid development expected this afternoon and evening. The vast majority of wind slabs will form near treeline and above treeline on NW-N-NE-E-SE aspects today. Wind slabs could also form in isolated areas on S-SW-W aspects, as well as in isolated areas below treeline.

Identify and avoid steep slopes where drifting snow is accumulating, slopes that are below cornice features, and steep slopes with newly formed wind pillows.

Avalanche Problem 2: Storm Slab
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The period of high intensity snowfall that is expected this afternoon and evening may create storm slabs. Varying snow levels today could also create upside down storm snow layering. These storm slabs could form in wind protected areas near treeline and below treeline on all aspects. On E-SE-S-SW-W aspects, new snow will likely deposit on top of melt-freeze crust formed yesterday. On NW-N-NE aspects new snow could deposit on top of either melt-freeze crust or recent storm snow, depending on elevation and slope angle.

Look for areas of snow surface cracking while making fresh tracks either uphill or down. Avoid steep slopes in areas where snow surface cracking exists.

Avalanche Problem 3: Loose Wet
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New snow that is deposited this morning could be rained on as snow levels rise today up to around 6,500' to 7,000'. Small loose wet avalanches could occur in areas that receive rain on snow today.

Avoid travel on or below steep slopes where rain is falling on a few inches or more of recent new snow.

Weather and CURRENT CONDITIONS
weather summary

A storm system will move through the forecast area today. The period of heaviest precipitation is expected to occur this afternoon and evening with cold front passage. Snow levels are starting out around 5,000' to 5,500' early this morning. Snow levels are forecast to rise to 6,500' to 7,000' today before lowering this afternoon. Ridgetop winds out of the SW are increasing this morning and have reached strong to gale force in speed. Snowfall is expected to taper to showers overnight. Saturday is expected to have continued snow showers and decreasing SW winds.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 24 to 29 deg. F.
Max. temperature in the last 24 hours: 33 to 40 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 40 mph
Maximum wind gust in the last 24 hours: 86 mph
New snowfall in the last 24 hours: Trace inches
Total snow depth: 122 to 174 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Cloudy skies with snow, possibly rain around 7,000'. Cloudy skies with snow. Mostly cloudy skies. A chance of snow showers in the morning, then a slight chance of snow showers in the afternoon.
Temperatures: 39 to 45 deg. F. 24 to 29 deg. F. 33 to 39 deg. F.
Wind Direction: SW SW SW
Wind Speed: 20 to 30 mph with gusts to 55 mph. 15 to 25 mph. Gusts to 50 mph decreasing to 40 mph after midnight. Light winds. Gusts up to 25 mph in the morning.
Expected snowfall: 6 to 12 in. 4 to 8 in. 1 to 2 in.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Cloudy skies with snow. Cloudy skies with snow. Mostly cloudy skies. A chance of snow showers in the morning, then a slight chance of snow showers in the afternoon.
Temperatures: 35 to 41 deg. F. 21 to 26 deg. F. 27 to 35 deg. F.
Wind Direction: SW SW SW
Wind Speed: 35 to 55 mph with gusts to 85 mph, increasing to 95 mph in the afternoon. 30 to 45 mph with gusts to 85 mph, decreasing to 20 to 30 mph with gusts to 60 mph after midnight. 15 to 20 mph. Gusts up to 45 mph decreasing to 25 mph in the afternoon.
Expected snowfall: 6 to 12 in. 4 to 8 in. 1 to 3 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