THIS AVALANCHE FORECAST EXPIRED ON April 20, 2018 @ 6:57 am
Avalanche Forecast published on April 19, 2018 @ 6:57 am
Issued by Andy Anderson - Tahoe National Forest - Sierra Avalanche Center

Periods of intense April sun this morning may cause enough warming for some small loose wet instabilities to form in isolated areas. MODERATE avalanche danger would result from this expected warming. If the forecasted cloud cover materializes sooner than expected, loose wet instabilities may be unlikely and less avalanche danger would exist. 

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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Below normal temperatures and light to moderate northerly winds combined with an expected increase in cloud cover by midday should keep wet snow instabilities to a minimum. However, some short periods of intense April sunshine this morning may cause enough warming for some wet snow to form. Some small human-triggered roller balls, pinwheels, and loose wet avalanches are possible in isolated areas on steep slopes that do receive sunshine this morning. Some of them could still entrain enough snow to cause problems for backcountry travelers. If the cloud cover materializes before midday, loose wet instabilities may be unlikely. If periods of sun continue into the afternoon, loose wet instabilities could become larger and more widespread.

Conditions can change quickly from cold soft snow to sunny warm unstable snow as soon as the sun hits the snow surface. If the snow starts to feel wet and sticky or small signs of loose wet instabilities like small roller balls or pinwheels start to occur, it is time relocate to a colder aspect. Shaded N aspects should experience the least warming and have the best potential for preserving some patches of colder snow.

recent observations
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* Yesterday variable conditions existed on Rubicon Peak with frozen breakable crusts on the E aspects and a mix of breakable crust and lingering soft snow on the northerly aspects. Widespread cloud cover and cool temperatures prevented loose wet instabilities.

Weather and CURRENT CONDITIONS
weather summary

The low pressure moving across the region should keep the temperatures cooler than and normal and allow widespread cloud cover this afternoon. Some scattered snow showers could still occur today with very little accumulation expected in most places. Winds have started to shift to the NE and NW and should continue through today. The forecast calls for the winds to remain light to moderate in speed. This small low pressure should exit the region completely tonight allowing skis to clear. By tomorrow expect the return of spring weather with sunny skies and daytime highs pushing into the 50's above 7000 ft.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 17 to 23 deg. F.
Max. temperature: 31 to 35 deg. F.
Average ridgetop wind direction: SW shifting to NE and NW
Average ridgetop wind speed: 25 to 35 mph until midnight | After midnight: 5 to 10 mph
Maximum ridgetop wind gust: 65 mph
New snowfall: Trace inches
Total snow depth: 50 to 94 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Thursday Thursday Night Friday
Weather: Periods of sun this morning becoming mostly cloudy by this afternoon. Scattered snow showers. Mostly cloudy becoming clear overnight. Scattered snow showers in the evening. Sunny
Temperatures: 38 to 43 deg. F. 24 to 29 deg. F. 51 to 56 deg. F.
Mid Slope Winds: Northwest Northwest Variable
Wind Speed: Light in the morning increasing to 10 to 15 mph with gusts to 30 mph in the afternoon 10 to 20 mph with gusts to 35 mph becoming light in the evening Light winds with gusts to 25 mph in the morning
Expected snowfall: Trace to 2 Trace with a chance of up to 1 0
For 8000 ft. to 9000 ft.
Thursday Thursday Night Friday
Weather: Periods of sun this morning becoming mostly cloudy by this afternoon. Scattered snow showers. Mostly cloudy becoming clear overnight. Scattered snow showers in the evening. Sunny
Temperatures: 32 to 38 deg. F. 22 to 27 deg. F. 46 to 52 deg. F.
Ridge Top Winds: Northwest North Northeast
Wind Speed: 15 to 20 mph with gusts to 25 mph increasing to 35 mph in the afternoon 15 to 25 mph with gusts to to 50 mph 15 to 25 mph with gusts to to 45 mph
Expected snowfall: Trace to 2 Trace with a chance of up to 1 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