THIS AVALANCHE ADVISORY EXPIRED ON March 2, 2017 @ 6:45 am
Avalanche Advisory published on March 1, 2017 @ 6:45 am
Issued by Brandon Schwartz - Tahoe National Forest

Areas of MODERATE avalanche danger are expected today. Wet loose avalanche activity is possible at all elevations. Some small new wind slabs likely formed above treeline last night due to a shift to E winds. Identify areas of concern and communicate a terrain management plan with travel partners.

2. Moderate

?

Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

?

Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

?

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
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

As air temperatures warm even further today, the gradual onset of wet loose instability over the last couple of days is expected to become more widespread. Roller ball activity occurring as snowfalls off of rocks and trees in expected on E-SE-S-SW-W aspects today. Small to medium sized natural and human triggered wet loose avalanches are possible in these areas of direct sun exposure.

Avoid travel on or below slopes 35 degrees and steeper where roller ball activity is occurring.

Avalanche Problem 2: Wind Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Wind speeds following the wind shift from SW to E yesterday evening have been strong enough to cause areas of blowing snow. This will have allowed for some small new wind slabs to form above treeline on S-SW-W-NW-N aspects.

Look for clues indicating the most recent drifting snow such as snow surface patterning (sastrugi) and newly formed wind pillows. Avoid suspect areas on slopes 35 degrees and steeper.

recent observations

Observations made yesterday in Negro Canyon (Donner Summit area) and on Ebbetts Pass revealed little in the way of signs of ongoing slab instability. Recent wind slab avalanche activity had occurred in the Ebbetts Pass area, but snowpit tests in both locations showed no signs of ongoing wind slab instability. Cornice drops, ski cuts, and snowmobile cuts on test slopes also failed to reveal any signs of instability. Areas of direct sun exposure have become increasingly dense and crusted in many areas.

Weather and CURRENT CONDITIONS
weather summary

High pressure will allow for continued sunny skies, light winds, and a warming trend to continue into Friday. Ridgetop winds shifted from SW to E yesterday evening. Light to moderate speed ridgetop winds this morning are forecast to decrease as the day progresses. The next storm system is expected to impact the region this weekend.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 16 to 23 deg. F.
Max. temperature in the last 24 hours: 26 to 34 deg. F.
Average wind direction during the last 24 hours: SW shifting to E
Average wind speed during the last 24 hours: SW 18 mph | E 21 mph
Maximum wind gust in the last 24 hours: SW 32 mph | E 34 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 138 to 188 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny skies. Clear skies. Sunny skies
Temperatures: 37 to 42 deg. F. 12 to 22 deg. F. 43 to 48 deg. F.
Wind Direction: E Variable Variable
Wind Speed: Light winds Light winds Light winds
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 36 to 41 deg. F. 14 to 22 deg. F. 41 to 46 deg. F.
Wind Direction: NE Variable Variable
Wind Speed: 10 to 15 mph with gusts to 25 mph in the morning, becoming light. Light winds Light winds
Expected snowfall: 0 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