THIS AVALANCHE ADVISORY EXPIRED ON January 29, 2014 @ 6:51 am
Avalanche Advisory published on January 28, 2014 @ 6:51 am
Issued by Brandon Schwartz - Tahoe National Forest

For today, avalanche danger is generally LOW. Pockets of MODERATE danger may form on NW-N-NE-E aspects on slopes 37 degrees and steeper due to rain on snow. Areas where light rain falls on sugary, faceted surface snow hold the greatest possibility of loose wet avalanches. Rain may fall as high as 8,000' to 9,500' across the forecast area today. Snow level will generally be higher in the southern half of the area. Avalanche danger is generally nonexistent on SE-S-SW-W aspects due to the lack of snow cover.

1. Low

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Above Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

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
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

In areas where light rain falls on the snowpack today, the possibility of natural and human triggered wet loose avalanches exists. This will be most problematic in locations where rain falls on well developed near surface facets. Near treeline and below treeline NW-N-NE aspects below 8,000 to 9,500' is where this avalanche problem is most likely to occur. Some isolated E aspects or above treeline areas may become involved as well. Steeper slope angles upwards of 37 degrees may be necessary for avalanches to initiate.

In areas where precipitation falls as snow, the new snow loading amounts of less than 1 inch are not expected to create any areas of slab avalanche instability.

recent observations

Observations made yesterday in Upper Ophir Creek (Mount Rose Backcountry) showed a continuation of the forecast area wide snowpack trend of significant near surface faceting and buried facet layers within the snowpack. The snowpack that exists near treeline and below treeline on NW-N-NE aspects has shown indications that it is weak but stable at this time. As precipitation moves through the forecast area this week, it is important to understand that despite the persistent drought pattern the existing snowpack on NW-N-NE aspects is in poor condition to handle new loading from either rain or snow. Once significant precipitation is added, the existing snowpack is likely to rapidly change from stable to unstable.

Weather and CURRENT CONDITIONS
weather summary

The first in a series of weather systems arrived last night and is lingering over the region. Light rain and a dusting of high elevation snow is on the peaks this morning. Very dry air at the lower elevations has kept rain from reaching the mountain valley floors. A slight chance of light rain and snow showers will continue through the day today. Snow level for today is expected at around 8,000' to 8,500' in the northern portion of the forecast area and around 9,000' to 9,500' today in the southern portion of the forecast area. A break in precipitation will occur tonight. Another round of rain and snow is forecast for tomorrow with snow level around 8,000' to 9,000'. A larger storm system is expected to move through the region on Thursday.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 33 to 38 deg. F.
Max. temperature in the last 24 hours: 45 to 50 deg. F.
Average wind direction during the last 24 hours: East shifting to West
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 25 mph
New snowfall in the last 24 hours: 0 to trace inches
Total snow depth: 8 to 15 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Tuesday Tuesday Night Wednesday
Weather: Cloudy skies with a slight chance of rain showers. Mostly cloudy skies. Mostly cloudy skies with a chance of rain.
Temperatures: 42 to 49 deg. F. 33 to 39 deg. F. 41 to 51 deg. F.
Wind Direction: Southwest Southwest West shifting to southwest
Wind Speed: 15 to 20 mph with gusts to 30 mph. 15 to 20 mph with gusts to 30 mph. 15 to 20 mph with gusts to 30 mph, increasing to 25 to 30 mph with gusts to 45 mph in the afternoon.
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Tuesday Tuesday Night Wednesday
Weather: Cloudy skies with a slight chance of rain and snow showers. Mostly cloudy skies. Mostly cloudy skies with a chance of rain and snow.
Temperatures: 38 to 45 deg. F. 28 to 35 deg. F. 40 to 46 deg. F.
Wind Direction: West West West
Wind Speed: 20 to 30 mph with gusts to 45 mph. 25 to 35 mph with gusts to 50 mph. 20 to 25 mph with gusts to 40 mph, increasing to 40 to 45 mph with gusts to 70 mph in the afternoon.
Expected snowfall: 0 to trace in. 0 in. 0 to 2 in.
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.