THIS AVALANCHE FORECAST EXPIRED ON March 7, 2019 @ 6:58 am
Avalanche Forecast published on March 6, 2019 @ 6:58 am
Issued by Steve Reynaud - Tahoe National Forest

CONSIDERABLE avalanche danger will exist at all elevations due to wind slab, storm slab, and loose wet avalanche problems.  Dangerous avalanche conditions could occur with natural and human triggered avalanches likely.   

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Near Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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Wind slabs will be likely on NW-N-NE-E-SE aspects in near and above treeline terrain as gale force SW winds along with heavy new snow impact our region.  Natural and human triggered wind slab avalanches are expected with wet slab characteristics possible as snow levels vary during the day.

Look for clues such as blowing snow, wind pillows, and cornice development to identify where the wind slab problem is likely to exist.  Make a travel plan to avoid steep wind loaded terrain, runout zones, and areas below large cornices. 

 

Avalanche Problem 2: Storm Slab
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Storm slab avalanches will become likely on all aspects in wind protected near and below treeline terrain as additional storm snow accumulates and snow levels fluctuate.  Storm slabs could be upside down and also have wet slab characteristics due to warming temperatures and/or rain on new snow.  These storm slab avalanches could be natural or human triggered and involve all of the recent storm snow.  Rain on new snow could lead to widespread instabilities. 

Avalanche Problem 3: Loose Wet
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Loose wet avalanches will be likely today on all aspects and elevations.  Varying snow levels could create widespread loose wet avalanches involving the recent storm snow.  Most are expected to be small in size and in the form of roller balls or pinwheels.  In isolated areas, larger loose wet avalanches could occur that entrain more snow.  Keep in mind that even small loose wet avalanches could have increased consequences when downslope terrain traps exist.

recent observations

*  Warm conditions were found on Silver Peak (Pole Creek area) yesterday.  A rain crust existed up to at least 8000' with some soft additional snow on top.  Small surface snow instabilities existed with a rain/snow mix below 7500'.

*  Observations from Frog Lake (Carson Pass area) also showed warm conditions with light rain during the day.  Snow transport was observed with wind slab development as well as storm slab cracking in below treeline terrain.

Weather and CURRENT CONDITIONS
weather summary

A warm Pacific storm that started yesterday will continue to bring wet snow, strong SW winds, and rain to our forecast area through Thursday.  Precipitation intensity should increase this morning through the day.  Snow levels are forecasted at around 6500', but could vary dramatically as storm intensity changes.  3 to 5'' of new snow has fallen in the last 24 hours with 4 to 10'' forecasted for areas above 8000' today.  All combined, storm totals through Thursday could reach 1 to 2' of wet heavy snow at the higher elevations along the Sierra Crest.  Snow levels should begin to drop late Thursday and into the weekend when additional snow may be possible. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 26 to 31 deg. F.
Max. temperature in the last 24 hours: 33 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 30 to 60 mph
Maximum wind gust in the last 24 hours: 112 mph
New snowfall in the last 24 hours: 3 to 5 inches
Total snow depth: 122 to 130 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Cloudy. Snow showers through the day. Slight chance of thunderstorms in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 95%. Cloudy. Snow showers and slight chance of thunderstorms in the evening, then snow showers likely after midnight. Snow levels below 7000 feet. Chance of precipitation is 80%. Cloudy. Snow showers likely. Snow levels below 7000 feet. Chance of precipitation is 65%.
Temperatures: 33 to 38. deg. F. 25 to 30. deg. F. 32 to 37. deg. F.
Mid Slope Winds: South 20 to 30 mph with gusts to 65 mph. Southwest 20 to 35 mph decreasing to 15 to 25 mph after midnight. Gusts up to 70 mph. Southwest 15 to 25 mph with gusts to 45 mph.
Expected snowfall: 80% probability of 3 to 10 inches. 20% probability of 10 to 16 inches. | SWE = 0.40-0.65 inch. 70% probability of 1 to 3 inches. 30% probability of 3 to 7 inches. | SWE = 0.15-0.25 inch. 60% probability of 1 to 2 inches. 40% probability of 2 to 4 inches. | SWE = up to 0.15 inch.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Cloudy. Snow showers through the day. Slight chance of thunderstorms in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 95%. Cloudy. Snow showers and slight chance of thunderstorms in the evening, then snow showers likely after midnight. Snow levels below 7000 feet. Chance of precipitation is 85%. Cloudy. Snow showers likely. Snow levels below 7000 feet. Chance of precipitation is 65%.
Temperatures: 29 to 34. deg. F. 21 to 26. deg. F. 28 to 34. deg. F.
Ridge Top Winds: South 35 to 55 mph with gusts to 100 mph. Southwest 40 to 60 mph decreasing to 30 to 45 mph after midnight. Gusts up to 95 mph. Southwest 20 to 35 mph with gusts to 65 mph.
Expected snowfall: 80% probability of 4 to 10 inches. 20% probability of 10 to 20 inches. | SWE = 0.40-0.65 inch. 70% probability of 1 to 4 inches. 30% probability of 4 to 8 inches. | SWE = 0.15-0.25 inch. 60% probability of 1 to 2 inches. 40% probability of 2 to 4 inches. | SWE = up to 0.15 inch.
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