THIS AVALANCHE FORECAST EXPIRED ON February 29, 2020 @ 6:40 am
Avalanche Forecast published on February 28, 2020 @ 6:40 am
Issued by Brandon Schwartz - Tahoe National Forest

Loose wet avalanches will be possible today in sun exposed areas during the late morning and afternoon hours due to weaker refreeze conditions and continued snow surface melt. MODERATE avalanche danger will exist today at all elevations.

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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For two consecutive nights now, air temperature inversion conditions kept overnight lows well above freezing in most locations at the mid and upper elevations. Another superficial snow surface refreeze is expected to have occurred last night reliant on radiational cooling of the snowpack. Increasing cloud cover last night may have decreased the efficiency of radiational cooling, possibly creating a thinner refreeze than what existed yesterday morning. By the late morning to midday hours today, this surface refreeze will weaken and melt away in sun exposed areas and a loose wet avalanche problem will exist for the rest of the day. Avalanche size is expected mostly at D1 with up to size D2 possible in areas where the upper snowpack is less consolidated.

Monitor snow surface melt throughout the day. The wetter and softer the upper snowpack becomes, the more likely it is for loose wet avalanches to occur. Once surface snow is more than a couple of inches deep, it’s time to exit avalanche terrain or move to an aspect with a firmer snow surface. Small loose wet avalanches could still have undesirable consequences in our relatively thin snow cover conditions as there are plenty of obstacles and hazards to hit.

recent observations
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* Observations made yesterday on Mt. Judah (Donner Summit area) showed weak superficial snow surface refreeze on treed slopes and a stronger but still superficial refreeze on open slopes. Signs of a developing loose wet avalanche problem were present on SE-S aspects by midday.

* Despite all of the warm weather in recent weeks, there are many areas on E aspects where the upper portion of the snowpack has yet to become a consolidated, springtime melt-freeze snowpack. This is increasingly prominent at the upper elevations. An observation received yesterday from Tamarack Peak (Mount Rose area) highlights this well.

* SE-S-SW aspects hold the most consolidated and well established melt-freeze snowpack conditions.

* NW-N-NE aspects remain highly variable, ranging from firm to soft with surface conditions ranging from ice to surface facets (also highlighted in yesterday's Tamarack Peak observation).

Weather and CURRENT CONDITIONS
weather summary

Some cloud cover moved into the forecast area last night ahead of an approaching cold front. Cloud cover is expected to increase as the day progresses, but periods of sunshine will still occur. Ridgetop winds shifted to the SW overnight and will increase in speed today, especially during the afternoon hours. These same winds are forecast to further increase tonight and tomorrow leading to strong SW winds. A few degrees of air temperature cooling are expected tomorrow with more dramatic and abrupt cooling tomorrow night with the passage of the cold front. A 2-4 hour period of post frontal accumulating snowfall followed by snow showers is expected Saturday night into Sunday. Check with NWS Reno for more info on this approaching weather system.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 34 to 41 deg. F.
Max. temperature: 46 to 54 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 11 mph
Maximum ridgetop wind gust: 28 mph
New snowfall: 0 inches
Total snow depth: 38 to 46 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy. Chance of precipitation is 0%. Mostly cloudy then becoming partly cloudy. Chance of precipitation is 0%. Partly cloudy. Chance of precipitation is 0%.
Temperatures: 49 to 55. deg. F. 29 to 34. deg. F. 41 to 46. deg. F.
Mid Slope Winds: Light winds becoming southwest 15 to 20 mph with gusts to 40 mph in the afternoon. Southwest 15 to 20 mph with gusts to 40 mph. Southwest 15 to 30 mph with gusts to 45 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy. Chance of precipitation is 0%. Mostly cloudy then becoming partly cloudy. Chance of precipitation is 0%. Partly cloudy. Chance of precipitation is 0%.
Temperatures: 43 to 49. deg. F. 27 to 32. deg. F. 36 to 42. deg. F.
Ridge Top Winds: Southwest around 15 mph with gusts to 30 mph increasing to 20 to 30 mph with gusts to 45 mph in the afternoon. Southwest 25 to 40 mph with gusts to 70 mph. Southwest 30 to 50 mph with gusts to 85 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