Eastern Sierra Avalanche Forecast - 1/10/15

Avalanche Advisory published on January 10, 2015 @ 6:20 pm
Issued by Sue Burak - Inyo National Forest
advisory discussion

Clouds, high relative humidity and very minor changes between night time lows and daytime highs are promoting another thin crust on all aspects. There are no observations from higher elevations above treeline. Typically, we see facets forming under crusts in winter snowpacks but this season, winter temperatures alternate with spring-like temperatures; the pattern swings from cold temperatures and faceting to mild temperatures and rounding facets. There is no trend in instability test results because test results are nil, X and NR. On a positive note, low sun angles help preserve the snow we do have.

recent observations

An observer reported “combat skiing” conditions in moist and unconsolidated snow on the backside of Mammoth two days ago. On Friday, I found a variable wet snow surface with a few areas where liquid water had drained into and around discontinuous layers of melt freeze crusts.  The photo shows what is known as a “flow finger”.  The snow below was clusters of rounded grains.

The snowpack was shallow with depths ranging from 30 to 50 cm (12 to 20 inches) and wind affected on this southwest slope.

weather summary

Cloudy weather with high relative humidity and temperatures hovering between 30 and 35 continue for the next two days. Drizzles of a mix of rain and snow are expected on Sunday with west winds picking up a little on Monday when a “stronger” weak system brings a few inches of snow to the Tahoe area.   Daytime highs will be in the mid to upper 30’s with lows around 30F.

The ridge builds back in and is expected to deflect next week’s storm into Washington state and Canada. Precipitation is expected in northwest California with little chance at this point of snowfall in our area.  

Weather Observations Between June (10,000 ft.) and Mammoth (11,000 ft.)
0600 temperature: 30 deg. F.
Max. temperature in the last 24 hours: 38 deg. F.
Average wind direction during the last 24 hours: WSW
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 27 mph
New snowfall in the last 24 hours: 0.4 inches
Total snow depth: 20 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Saturday Saturday Night Sunday
Weather: mostly cloudy mostly cloudy partly sunny
Temperatures: 27-36 deg. F. 25-30 deg. F. 30-35 deg. F.
Mid Slope Winds: W W W
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
Saturday Saturday Night Sunday
Weather: mostly cloudy cloudy mostly cloudy
Temperatures: 28 deg. F. 25 deg. F. 28 deg. F.
Ridge Top Winds: NW W W
Expected snowfall: .5 in. 0 in. 0 in.
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