THIS AVALANCHE FORECAST EXPIRED ON March 13, 2019 @ 6:49 am
Avalanche Forecast published on March 12, 2019 @ 6:49 am
Issued by Brandon Schwartz - Tahoe National Forest

MODERATE avalanche danger continues near treeline and above treeline due to the possibility of encountering unstable wind slabs. Below treeline avalanche danger is LOW.

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.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
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    Historic
    Very Large
    Large
    Small

Ridgetop winds continue to shift back and forth between SW and NE. Problematic wind slabs have been observed on all aspects in near treeline and above treeline areas. Wind slab avalanches have occurred each of the past three days. The possibility of encountering an unstable wind slab continues today on any aspect in near treeline to above treeline terrain. Sensitivity to triggering may be stubborn.  Avalanche size up to D2 is expected.

Due to the recent wind shifts, expect to encounter wind slabs on a variety of aspects while moving through terrain. Evaluate near treeline and above treeline terrain slope by slope for clues indicating the presence or absence of wind slabs. Unless a slope has been heavily wind scoured, anticipate that a problematic wind slab is present. If in doubt, opt for the more conservative terrain choices of your travel plan. Softer, less dense snow with less avalanche hazard exists on sun and wind protected slopes below treeline.

Forecast discussion

Some very minor amounts of snow surface warming may occur today in sun exposed areas at low to mid elevations. The approaching cold front is expected to limit snow surface warming this afternoon and keep a loose wet avalanche problem from forming today.

recent observations

* Wind slab avalanches size D1 to D2 have occurred each of the past three days in near to above treeline areas. A small (size D1) wind slab avalanche was intentionally human triggered by cornice fall yesterday morning on a NE aspect in above treeline terrain on Anderson Peak (Upper Cold Stream area).

* NE winds were observed to create periods of moderate to intense blowing snow yesterday morning in some near treeline and above treeline areas.

* Buried surface hoar has been reported 1 to 2 feet below the snow surface in the Ebbetts Pass and the Spooner/Kingsbury areas.

* No signs of problematic instability have been reported from wind protected areas below treeline over the past few days.

* Snow surface warming has created thin surface crust in many sun exposed areas.

Weather and CURRENT CONDITIONS
weather summary

Sunny skies this morning will give way to increasing cloud cover and increasing SW ridgetop winds ahead of an approaching cold front. Frontal passage is expected to occur late this afternoon into this evening bringing cloud cover, colder air temperatures, and a short period of light snow showers. Ridgetop winds are forecast to shift to the N tonight and to the NE tomorrow. Maximum daytime air temperatures are expected to be about 5 degrees colder tomorrow than today. High pressure is forecast to build over the region for the end of this week.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 20 to 24 deg. F.
Max. temperature in the last 24 hours: 24 to 34 deg. F.
Average wind direction during the last 24 hours: NE
Average wind speed during the last 24 hours: 33 mph
Maximum wind gust in the last 24 hours: 62 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 125 to 165 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Tuesday Tuesday Night Wednesday
Weather: Sunny then becoming partly cloudy. Chance of snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 40%. Mostly cloudy then becoming partly cloudy. Chance of snow in the evening. Snow levels below 7000 feet. Chance of precipitation is 55%. Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 33 to 38 deg. F. 10 to 15 deg. F. 28 to 33 deg. F.
Mid Slope Winds: Light winds becoming southwest 15 to 25 mph with gusts to 45 mph in the afternoon. North 15 to 20 mph. Gusts up to 40 mph decreasing to 30 mph after midnight. Light winds becoming northeast around 15 mph in the afternoon. Gusts up to 30 mph.
Expected snowfall: Trace to 1 inch. | SWE = less than 0.10 inch. Trace to 1 inch. | SWE = less than 0.10 inch. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Tuesday Tuesday Night Wednesday
Weather: Sunny then becoming partly cloudy. Chance of snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 40%. Mostly cloudy then becoming partly cloudy. Chance of snow in the evening, then slight chance of snow showers after midnight. Snow levels below 7000 feet. Chance of precipitation is 55%. Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 29 to 35 deg. F. 8 to 13 deg. F. 24 to 30 deg. F.
Ridge Top Winds: Southwest around 15 mph with gusts to 35 mph increasing to 25 to 35 mph with gusts to 65 mph in the afternoon. North 15 to 30 mph. Gusts up to 55 mph decreasing to 45 mph after midnight. Northeast 15 to 30 mph with gusts to 60 mph.
Expected snowfall: Trace to 1 inch. | SWE = less than 0.10 inch. Trace to 1 inch. | SWE = less than 0.10 inch. 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