Eastern Sierra Avalanche Forecast - 1/29/14

THIS AVALANCHE ADVISORY EXPIRED ON January 30, 2014 @ 8:02 am
Avalanche Advisory published on January 29, 2014 @ 8:02 am

Issued by Sue Burak - Inyo National Forest

Bottom Line

How to read the advisory

SPECIAL AVALANCHE STATEMENT

The first winter storm in almost 2 months will impact the area tonight and tomorrow. One to two feet of snow is expected to fall in the mountains abovoe 8,500 ft tonight and most of the day tomorrow.

While expected snowfall amounts do not meet the level necessary to issue an Avalanche Warning, significant public use expected during dangerous avalanche conditions over the next two days. Over a foot of new snow accompanied by strong winds will fall on top of 6-15" of weak faceted snow that has no cohesion.

This Avalanche Statement expires in 24 hours. The first avalanche advisory of the winter of 2013-2014 will be issued tomorrow morning.

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Above Treeline

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Near Treeline

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Below Treeline

advisory discussion

Last week I wrote , “in order to have an avalanche, you need a weak layer and a slab”. The snowpack in all the places we have traveled in the past month, is the same- well developed facets and depth hoar. Previous snowpack discussions details the multiple layers of weak large facets sandwiched between melt freeze crusts. The bad news is that is on upper elevation north facing slopes, the old snow will become THE persistent weak layer capable of producing moderate sized avalanches once more snow layers are added. It covers large enough portions of the starting zones to produce a big enough avalanche to injure or kill a person. These places include the following

Tele Bowl, the Hose, Mammoth Rock , Mammoth Bowl, Red Cone, Hammil Bowl to name a few. These are the areas are exactly where we will want to go with 10 to up to 20 inches of new snow. Collapsing or "Whoomping" underfoot is a tell tale sign. It's easy to dig down and see if there is old sugary snow under the new snow.

Early season excitement can be hard to control. Get your gear out, change batteries in your avalanche beacons and think about the ways you can manage the avalanche risk. For an excellent pre season video on preparing your avalanche gear, please view this video from the Gallatin Avalanche Center:

http://www.youtube.com/watch?v=xVbM8OCUvl8&list=PLXu5151nmAvR37ZzpTrs8293OfFezBjJB&index=42

recent observations

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I skied into an area by Minaret Summit and found the layers in my snowpit to be mostly unchanged from a visit 10 days ago. I even sunk to the ground in facets when I stepped out of my skis; a sign of unsupportable snow and poor snow structure.

Weather and CURRENT CONDITIONS

weather summary

The first winter storm in nearly two months moves into the area this afternoon and evening. Snow levels will be initially high- around 7500 to 8,000 ft this evening, dropping to 55000 ft this evening. Heaviest snow fall is expected to occur tonight and into mid day Thursday. Above 8000 feet, this looks to be a decent base builder for the mountains, and while we normally like that in November, we will take it this year in January.

Weather Observations Between June (10,000 ft.) and Mammoth (11,000 ft.)

Weather Station Map

Weather Station Table

0600 temperature:	40 deg. F.
Max. temperature in the last 24 hours:	50 deg. F.
Average wind direction during the last 24 hours:	SW
Average wind speed during the last 24 hours:	15 mph
Maximum wind gust in the last 24 hours:	43 mph
New snowfall in the last 24 hours:	0 inches
Total snow depth:	14 inches

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:	clouds and windy	cloudy, 50% chance of snow	100% of snow
Temperatures:	44 deg. F.	29 deg. F.	29 deg. F.
Mid Slope Winds:	SW	SW	SW
Expected snowfall:	0 in.	3 in.	12 in.