THIS AVALANCHE FORECAST EXPIRED ON March 31, 2019 @ 6:59 am
Avalanche Forecast published on March 30, 2019 @ 6:59 am
Issued by Andy Anderson - Tahoe National Forest - Sierra Avalanche Center

LOW danger will increase to MODERATE avalanche danger at all elevations today as the day warms up. Loose wet avalanches will represent today's main avalanche problem, but some isolated and unlikely wind slab problems may also still exist in a few areas. 

2. Moderate

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

2. Moderate

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

2. Moderate

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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
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Strong sunshine and warm weather should quickly melt through last night's refreeze. Loose wet avalanches large enough to cause serious problems for backcountry travelers could occur today, especially on long, steep, sun-exposed slopes. E-SE-S-SW-W aspects will be most susceptible since they will experience the full force of the spring sunshine. Some wet snow may form on sun-exposed northerly aspects as well.

Wet, heavy surface snow and/or pinwheels or roller balls formed as the refreeze melts can foreshadow larger loose wet avalanche activity. Once the melt starts, it is time to seek out colder more shaded aspects. These colder aspects are the areas where softer snow may still exist and should hold less hazardous avalanche conditions. 

Avalanche Problem 2: Wind Slab
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Settlement and consolidation in the new snow should make triggering a wind slab avalanche unlikely in the majority of areas today. Unlikely does not mean impossible. An isolated wind slab failure cannot be ruled out in some complex or extreme terrain (like couloirs, cliffy areas, unsupported slopes, and steep convex rollovers) or in response to a very large trigger (like a large cornice collapse).

Variable, challenging, wind affected snow conditions will exist in areas where difficult to trigger wind slabs may still linger. Avoiding these less fun snow conditions in favor of the softer snow that should still remain in more sheltered terrain could provide more enjoyable recreation and help avoid potentially unpleasant wind slab surprises.

recent observations

* Yesterday two human-triggered wind slabs were reported: one snowmobile triggered near Indian Valley and one triggered by a ski cut piece of cornice on Mt. Judah. Both of these had crown depths of ~ 1 ft. Both occurred on steep-exposed wind-loaded slopes in near and above treeline terrain.

* Observations in exposed above treeline areas on Mt. Rose and on Trimmer Peak also found signs of lingering wind slabs. On Trimmer, a small test slope failed in response to a ski cut. On Rose, some cracking occurred in response to a ski kick on a previously undercut slope. 

* Observations from less exposed areas around Blue Lakes, Indian Valley, Mt. Rose, and Trimmer Peak did not find signs of lingering instability despite numerous ski and snowmobile cuts on test slopes.  Warm wet surface snow and some small inconsequential warming instabilities did start to form by the afternoon in all of these areas on sun-exposed slopes.

 

Weather and CURRENT CONDITIONS
weather summary

A high-pressure ridge over the area will keep the weather warm and sunny through the weekend. Winds decreased and should remain calm in most places. Some light E winds may continue along upper elevation ridges. Expect daytime highs to climb into the 40's above 7000 ft today and into the low 50's tomorrow. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 19 to 24 deg. F.
Max. temperature in the last 24 hours: 34 to 37 deg. F.
Average wind direction during the last 24 hours: SW shifting to ENE
Average wind speed during the last 24 hours: 10 to 20 mph
Maximum wind gust in the last 24 hours: 30 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 114 to 164 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Saturday Saturday Night Sunday
Weather: Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%. Clear. Snow levels below 7000 feet. Chance of precipitation is 0%. Sunny then becoming partly cloudy. Snow levels 7000 feet. Chance of precipitation is 0%.
Temperatures: 40 to 45 deg. F. 21 to 26 deg. F. 48 to 54 deg. F.
Mid Slope Winds: Light winds. Light winds. Light winds.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%. Clear. Snow levels below 7000 feet. Chance of precipitation is 0%. Sunny. Snow levels 7000 feet. Chance of precipitation is 0%.
Temperatures: 34 to 40 deg. F. 19 to 24 deg. F. 44 to 52 deg. F.
Ridge Top Winds: East around 10 mph. East around 10 mph. Southwest around 15 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
Disclaimer

This avalanche forecast is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This forecast 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 forecast applies only to backcountry areas outside established ski area boundaries. This forecast describes general avalanche conditions and local variations always occur. This forecast expires 24 hours after the posted time unless otherwise noted. The information in this forecast is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the avalanche forecast call (530) 587-3558 x258