THIS AVALANCHE FORECAST EXPIRED ON April 7, 2016 @ 6:58 am
Avalanche Forecast published on April 6, 2016 @ 6:58 am
Issued by Andy Anderson - Tahoe National Forest - Sierra Avalanche Center

After a short window of LOW danger early this morning, MODERATE danger will form on slopes steeper than 35 degrees on all aspects and elevations starting in the mid morning hours with the most sun-exposed aspects and progressing to other aspects during the day. Loose wet avalanches large enough to threaten backcountry travelers will be possible again today. Evaluate snow and terrain carefully. Identify and avoid the areas where wet snow deep enough for loose wet avalanches exists. 

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

Even though temperatures remained well above freezing in most areas last night, clear skies should have allowed the snowpack to radiate enough heat into the night sky for some of yesterday's wet snow to refreeze. This thin refreeze will not last long, and the intense April sun and warm daytime temperatures will quickly melt through last night's refreeze leaving deep wet snow on the slopes. Once this happens, the ice bonds that give the snowpack strength will have melted away allowing the remaining loose wet snow to slide down steep slopes in the form of loose wet avalanches. 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 NW-N-NE aspects could also see enough sun for wet snow instabilities to form at all elevations. Most of the wet snow instabilities should manifest as loose wet avalanches but other forms of wet snow instabilities like glide cracks or wet slabs are not impossible. 

Once last night's melt-freeze crust starts to become unsupportable and the wet snow starts to deepen, it becomes unstable very quickly. As soon as the snowpack starts becoming unsupportable, it is time to move to more frozen aspects, onto lower angle slopes away from anything steep, or to get off the snow and start the BBQ on the beach. Stepping off your equipment and 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. Terrain traps like gullies, creeks, and cliffs can greatly increase the risk of any size loose wet avalanches.

recent observations
Submit Observations

Yesterday observations on Rubicon Peak showed melt-freeze conditions on all aspects. The snow surfaces had already started to soften by 10 am on any sun-exposed slopes on all aspects and elevations. By 11:10 am the snow on northerly aspects had become wet and sticky as the melt-freeze snow softened and transitional snow below it also became wet. Sun-exposed east aspects held corn snow conditions above 8000 ft. with 2-3 inches of corn resting on top of a supportable melt-freeze crust at 11:30 am. At this time the overnight melt-freeze crust had almost become unsupportable on the east aspects below 8000 ft.

Reports of additional wet snow issues from 4/3 and 4/4 including loose wet snow avalanches in the Emerald Bay chutes and glide cracks on Pyramid Peak also came in yesterday evening. 

Weather and CURRENT CONDITIONS
weather summary

Last night the forecast area saw another night with mostly above freezing temperatures, and today will bring another day of warm sunny weather. The forecast calls for daytime highs in the upper 50's above 7000 ft. with some areas breaking into the 60's between 7000 and 8000 ft. Expect the winds to remain light and out of the east. This warm, sunny, dry weather should continue through tomorrow, but some thin cloud cover may start to develop tomorrow afternoon and evening and the winds should start to increase ahead of an approaching storm. For more details and the latest updates on the storm check in with the Reno NWS.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 33 to 46 deg. F.
Max. temperature: 47 to 55 deg. F.
Average ridgetop wind direction: East
Average ridgetop wind speed: 10 to 20 mph
Maximum ridgetop wind gust: 37 mph
New snowfall: 0 inches
Total snow depth: 67 to 110 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 Clear Sunny
Temperatures: 57 to 63 deg. F. 34 to 40 deg. F. 54 to 61 deg. F.
Mid Slope Winds: East East Variable
Wind Speed: 10 mph 10 mph decreasing overnight Light
Expected snowfall: 0 0 0
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny Clear Sunny
Temperatures: 53 to 59 deg. F. 32 to 39 deg. F. 50 to 57 deg. F.
Ridge Top Winds: East East East
Wind Speed: 10 to 20 mph with gusts to 30 mph in the morning 10 to 15 mph 10 to 15 mph with gusts to 25 mph increasing to 20 to 25 mph with gusts to 35 mph in the afternoon
Expected snowfall: 0 0 0
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