Eastern Sierra Avalanche Forecast - 1/15/14

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THIS AVALANCHE ADVISORY EXPIRED ON January 16, 2014 @ 7:00 am
Avalanche Advisory published on January 15, 2014 @ 7:00 am
Issued by Sue Burak - Inyo National Forest
bottom line

The dry weather continues. There is not enough snow to warrant avalanche danger ratings. Once snow comes, advisories will resume. For updated snowpack conditions, see the text discussion. 

How to read the advisory

Bottom Line

The dry weather continues. There is not enough snow to warrant avalanche danger ratings. Once snow comes, advisories will resume. For updated snowpack conditions, see the text discussion. 

advisory discussion

With sparse snow cover, there is a high level of variability in snow depths but not in the snow structure. Over the past week, snow depths range from bare to 4” to 24” depending on aspect, elevation, slope configuration and whether slopes are shaded or non-shaded.  On Tuesday, we visited some north facing mid elevation terrain in the Minaret Summit area.   The snow structure is similar to the snow in Rock Creek and  in the Mammoth Basin.  The sun crusts at the snow surface and within the “snowpack” assist the faceting process.

It appears that the depth hoar is becoming larger, better developed and increasing in density.  Some of the increase in density comes from gravity – the individual grains slip and rotate with their neighboring grains. Snow becomes stronger more by the sintering process. With a temperature gradient of  1.8C from the ground to the snow surface in 34 cm of snow, the faceting process will continue until more snow falls, air temperatures increase or spring comes. 

CURRENT CONDITIONS Weather Observations Between June (10,000 ft.) and Mammoth (11,000 ft.)
0600 temperature: 20 deg. F.
Max. temperature in the last 24 hours: 47 deg. F.
Average wind direction during the last 24 hours: NE
Average wind speed during the last 24 hours: 10-20 mph
Maximum wind gust in the last 24 hours: 20 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 15-20 inches
weather

As we all probably know, the National Weather Service forecast calls for mostly sunny skies for the week. Highs will reach the mid 40’s today at the 8,000 to 10,000 ft elevations, then warm a few degrees to around 50 F on Thursday and Friday.  Nights will be cool with lows in the low to mid 20’s.

The latest long range diagnostics continue to point toward high confidence in a blocking ridge of high pressure over California and Nevada through at least mid to late next week. This will shift the storm track well north of the area. This ridge is unusually strong and persistent.

There is a small chance of a weak low pressure storm squeaking in under the ridge and producing some light precipitation in the Sierra and slightly increased winds next week but confidence is low. In general light winds and weak-moderate valley inversions will be the rule.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
  Wednesday Wednesday Night Thursday
Weather: sunny clear sunny
Temperatures: 45 deg. F. 20 deg. F. 50 deg. F.
Wind direction: NE NE NE
Wind speed: 10 10 15
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
  Wednesday Wednesday Night Thursday
Weather: sun clear sun
Temperatures: 42 deg. F. 18 deg. F. 48 deg. F.
Wind direction: NE NE W
Wind speed: 10-20 10-20 20
Expected snowfall: 0 in. 0 in. 0 in.
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