THIS AVALANCHE FORECAST EXPIRED ON December 3, 2017 @ 6:53 am
Avalanche Forecast published on December 2, 2017 @ 6:53 am
Issued by Brandon Schwartz - Tahoe National Forest

For the daylight hours today, LOW avalanche danger continues for all elevations. Depending on new snowfall amounts, areas of MODERATE avalanche danger may form tonight. A wind slab avalanche problem is expected to develop as winds increase today and new snowfall arrives this evening.

1. Low

?

Above Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

?

Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

?

Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Wind Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

As SW ridgetop winds increase to gale force today, any snow still available for wind transport will allow for small wind slab formation in near and above treeline areas on NW-N-NE-E-SE aspects. Following the onset of snowfall this afternoon/evening, wind slabs will have a better opportunity to increase in size, especially if the upper end of forecast snowfall amounts are reached. Isolated wind slabs capable of size D1 avalanches today could develop into location specific or widespread wind slabs capable of size D2 avalanches during the overnight hours depending on snowfall amounts.

recent observations

-Areas with a usable snowpack are generally limited to locations above 8,000', but extend down to 7,300' in isolated areas.

-High density rain crust exists near and sometimes at the snow surface in most locations below 10,000'.

-Melt-freeze surface conditions exist on southerly aspects and cold dry faceted surface snow can be found on northerly aspects and in other shaded areas.

-Surface hoar up to 10 mm in crystal size has been noted in the Carson Pass and Donner Summit areas.

-The layers deeper in the snowpack are well bonded and previously affected by rain and melt.

Weather and CURRENT CONDITIONS
weather summary

A strong cold front and associated storm system will move through the forecast area today and tomorrow. SW ridgetop winds are on the increase this morning, expected to become gale force by this afternoon. Light snowfall is expected to begin this afternoon, increasing some during the overnight hours. Snowfall amounts remain uncertain with this storm, but up to 6 inches along the Sierra Crest is the current forecast thinking. As the storm exits the region Sunday afternoon, winds begin to decrease, but remain moderate to strong in speed.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 30 to 36 deg. F.
Max. temperature in the last 24 hours: 39 to 43 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 28 mph
Maximum wind gust in the last 24 hours: 45 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 14 to 32 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Saturday Saturday Night Sunday
Weather: Partly cloudy skies, becoming mostly cloudy. Mostly cloudy skies with a chance of snow. Mostly cloudy skies, becoming partly cloudy. A chance of snow.
Temperatures: 41 to 47 deg. F. 22 to 27 deg. F. 28 to 33 deg. F.
Winds: SW SW SW shifting to W
Expected snowfall: 0 to trace in. 1 to 3 in. Likely 1 to 3 in. | Possible 4 to 5 in.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Partly cloudy skies, becoming mostly cloudy. Mostly cloudy skies with a chance of snow. Mostly cloudy skies, becoming partly cloudy. A chance of snow.
Temperatures: 37 to 43 deg. F. 19 to 25 deg. F. 24 to 30 deg. F.
Winds: SW SW SW shifting to W
Expected snowfall: 0 to trace in. Likely 1 to 4 in. | Possible 4 to 6 in. Likely 1 to 4 in. | Possible 4 to 6 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