THIS AVALANCHE ADVISORY EXPIRED ON April 2, 2016 @ 6:53 am
Avalanche Advisory published on April 1, 2016 @ 6:53 am
Issued by Andy Anderson - Tahoe National Forest

MODERATE avalanche danger will form on slopes steeper than 35 degrees on E-SE-S-SW-W aspects at all elevations and may form on some sun-exposed near and below treeline NW-N-NE aspects as daytime warming makes loose wet avalanches possible again today. Clues like sinking into wet snow above your boot tops or small point releases, roller balls, or pinwheels can help determine when to move to more frozen aspects, onto lower angle slopes, or to switch to a different afternoon activity.

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

The recent snow still has not experienced enough melt-freeze cycles to form good drainage channels in many areas. More sunshine, warmer temperatures, and less wind today mean that loose wet avalanches will become possible as last night's refreeze melts leaving a layer of wet snow sitting on top of old frozen crusts. These old frozen crusts make efficient bed surfaces for the wet snow to slide on. Like yesterday some of the loose wet avalanches that occur today could entrain enough snow to cause problems for backcountry travelers especially in areas where the loose wet avalanches involve terrain traps. Slopes steeper than 35 degrees on sun-exposed E-SE-S-SW-W aspects at all elevations will hold the best potential for loose wet avalanches since they should experience the most warming, but some of the near and below treeline NW-N-NE aspects could also see enough sun for some wet snow instabilities to form. Expect to find deeper wet snow and larger wet snow issues in the Mt. Rose backcountry where the most snow fell during the recent storm. In areas along the Sierra Crest south of Highway 50 where less recent snow exists, the wet snow issues should remain smaller and entrain less snow. Wet snow instabilities in areas north of Highway 50 along the Sierra Crest and on the east side of Lake Tahoe south of Mt. Rose should fall somewhere between the other two zones, and the size of loose wet snow instabilities will depend on the amount of recent snow that exists in a specific area.

Sinking into wet snow above your boot tops and small surface instabilities like roller balls, pinwheels, or point releases can provide clues that enough wet snow has formed for larger loose wet avalanches to become an issue. Moving to more frozen slopes or onto lower angle slopes off and away from slopes 35 degrees or steeper before deep wet snow exists on a slope represents a wise choice for today. Terrain traps like gullies, creeks, and cliffs can greatly increase the risk of any size loose wet avalanches.

recent observations

Yesterday on the Fireplug in the Mt. Rose backcountry, wet snow had formed above frozen crusts on any sun exposed slopes where recent snow existed by mid morning. Skier triggered loose wet slides occurred on steep NE facing slopes and on E-SE facing test slopes. Upper elevation northerly aspects held scoured crusts and more sheltered lower elevation northerly slopes had breakable crusts on the surface in most places with a few isolated patches of soft cold snow remaining in some areas. 

Weather and CURRENT CONDITIONS
weather summary

A high pressure ridge over the region will keep the weather sunny, warm, and dry. The forecast calls for daytime highs above 7000 ft. in the upper 40's to low 50's for today with slightly warmer temperatures tomorrow. Winds should remain mostly calm until tomorrow when a southwest breeze could affect the upper elevations due to a small, weak system moving across northern CA. This system could also bring a few clouds to the area tomorrow afternoon. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 34 to 38 deg. F.
Max. temperature in the last 24 hours: 44 to 51 deg. F.
Average wind direction during the last 24 hours: Southwest to northeast
Average wind speed during the last 24 hours: 10 to 15 mph
Maximum wind gust in the last 24 hours: 33 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 75 to 117 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Sunny Clear Sunny to partly coudy
Temperatures: 46 to 53 deg. F. 25 to 32 deg. F. 48 to 55 deg. F.
Wind Direction: Variable Variable Variable
Wind Speed: Light Light Light
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Sunny Clear Sunny to partly cloudy
Temperatures: 42 to 49 deg. F. 26 to 33 deg. F. 44 to 51 deg. F.
Wind Direction: Variable Variable Southwest
Wind Speed: Light Light 10 to 15 mph
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