THIS AVALANCHE FORECAST EXPIRED ON April 15, 2019 @ 6:49 am
Avalanche Forecast published on April 14, 2019 @ 6:49 am
Issued by Brandon Schwartz - Tahoe National Forest

LOW avalanche danger will transition to MODERATE avalanche danger at all elevations today in response to daytime warming. As last night's snow surface refreeze becomes unsupportable, a loose wet avalanche problem will develop 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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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Increasing cloud cover and above freezing air temperatures last night are expected to have allowed for a weaker snow surface refreeze last night as compared to 24 hours ago. As daytime warming progresses, a loose wet avalanche problem will develop on all aspects at all elevations. Avalanche size is generally expected at D1 with the possibility of an isolated size D2.

Be ready to exit avalanche terrain early in the day today, especially if last nights refreeze was not particularly strong or thick in your chosen area of travel. Continuously monitor snow surface supportability and surface crust strength and thickness. When the surface crust loses supportability or melts away and the deeper wet snow is exposed, the loose wet avalanche problem is present and it is time to adjust terrain choices accordingly.  Keep in mind that moderate to strong ridgetop winds may slow melt rates near the ridgetops while more rapid melt rates occur mid slope and below.

recent observations

* Yesterday, very strong overnight refreezes were noted in the Donner Summit and Luther Pass areas. Supportable snow surface conditions lasted well into the afternoon hours on all aspects.

* Snow surface refreeze conditions last night were much less ideal than the night before due to building cloud cover and warmer air temperatures.

* Snowpack instability is expected to occur near the surface, with the deeper snowpack generally well bonded. The exception might be glide cracks.

Weather and CURRENT CONDITIONS
weather summary

Cloud cover increased last night ahead of two weak weather systems that will move through the region today and tomorrow. Light rain and snow showers may start as early as this afternoon, becoming more widespread tonight and tomorrow. SW ridgetop winds have allowed for little to no air temperature inversion across the forecast area this morning.  Above freezing air temperatures exist at many locations below 8,000' this morning and extend higher in some areas. Clearing weather is expected Tuesday afternoon with high pressure building for Wednesday through Friday.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 31 to 37 deg. F.
Max. temperature in the last 24 hours: 42 to 51 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 30 mph
Maximum wind gust in the last 24 hours: 54 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 103 to 151 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Sunday Sunday Night Monday
Weather: Partly cloudy then becoming mostly cloudy. Snow levels 7500 feet increasing to 8500 feet in the afternoon. Chance of precipitation is 10%. Mostly cloudy. Slight chance of showers through the night. Snow levels 8000 feet. Chance of precipitation is 25%. Partly cloudy then becoming mostly cloudy. Chance of showers. Snow levels 7500 feet. Chance of precipitation is 50%.
Temperatures: 46 to 52 deg. F. 29 to 34 deg. F. 42 to 48 deg. F.
Mid Slope Winds: Southwest 15 to 20 mph with gusts to 45 mph increasing to 15 to 30 mph with gusts to 60 mph in the afternoon. Southwest 15 to 30 mph. Gusts up to 60 mph decreasing to 45 mph after midnight. Southwest 15 to 20 mph with gusts to 45 mph increasing to 15 to 30 mph with gusts to 55 mph in the afternoon.
Expected snowfall: No accumulation. | SWE = none. Up to 2 inches. | SWE = less than 0.10 inch. 70% probability up to 2 inches. 30% probability of 2 to 4 inches. | SWE = up to 0.15 inch.
For 8000 ft. to 9000 ft.
Sunday Sunday Night Monday
Weather: Partly cloudy then becoming mostly cloudy. Snow levels 7500 feet increasing to 8500 feet in the afternoon. Chance of precipitation is 10%. Mostly cloudy. Chance of showers. Snow levels 8500 feet decreasing to 7500 feet after midnight. Chance of precipitation is 25%. Partly cloudy then becoming mostly cloudy. Chance of showers. Snow levels 7500 feet. Chance of precipitation is 50%.
Temperatures: 40 to 48 deg. F. 26 to 31 deg. F. 36 to 42 deg. F.
Ridge Top Winds: Southwest 30 to 45 mph with gusts to 70 mph. Southwest 30 to 45 mph with gusts to 80 mph. Southwest 25 to 35 mph increasing to 30 to 45 mph in the afternoon. Gusts up to 80 mph.
Expected snowfall: No accumulation. | SWE = none. 80% probability up to 1 inch. 20% probability up to 2 inches. | SWE = less than 0.10 inch. 70% probability up to 3 inches. 30% probability of 3 to 5 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