March 27, 2013

Advisory and forecast based on observational knowledge and weather forecast available at the time of posting.  Accuracy is subject to temporal and spatial variability.  Read the disclaimer, use at your own risk, and conduct your own assessment of conditions accordingly.

Wednesday:

ds-mod

see the complete danger scale

What you need to know:

On average, our most recent storm deposited nearly two feet of dry, low density snow in the upper elevations.  Small pockets of slightly reactive soft slab were found along the Peak 3-4.5 ridge with one sizable soft slab (not large enough to bury but definitely big enough to knock someone over and take them for a short ride) that pulled out in very steep terrain (see that observation here).  Observers in the South Fork Eagle River valley reported one whoomph and some small cracking in the alders on Tuesday.  Everyone had smiles on their faces and enjoyed this much needed welcome to spring, but kept slope angles low and didn’t expose themselves to high consequence terrain.

Danger trend:

Decreasing through Wednesday.

Primary Concern:

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Signs of instability in our new snow from Monday were found from the north to the south of the advisory zone Tuesday, with the most significant event reported being a sizeable soft slab that pulled out in a steep chute off Peak 4.  Expect the possibility of human-triggered soft slabs in the new snow to remain through Wednesday.

The weather forecast for Wednesday is currently calling for warmer temps and sunnier skies than Tuesday.  While I don’t expect enough warming to significantly increase avalanche hazard, it will be important to pay attention to the sun’s affect on the snow if it comes out in force.  It’s spring, the days are becoming quite longer, and the sun’s intensity has increased.  Keep this in mind when assessing the avalanche hazard and be mindful of signs of warming such as point releases (likely from warming rocky areas), rollerballs, and moistening snow.

Secondary Concern:

wind-slab-12

Winds are forecast to become strong enough to start transporting snow through Wednesday.  Look for clues to snow transport such as blowing snow, pluming, and freshly wind-deposited snow with a pillowy look.  If the forecast holds, while the winds might become strong enough to move some snow around they shouldn’t become strong enough to cause widespread redistribution.

Travel Advice:

Wednesday should prove to be another great day on the Chugach Front and Eagle River slopes, but human triggered avalanches will still be possible.  Big, steep, open slopes as well as steep slopes with exposure should still be approached with a great deal of caution.

Mountain Weather:

Expect mountain temperatures in the upper teens with light-moderate winds and partly cloudy skies.

Avalanche Outlook:

Thursday, March 28

While the new snow will continue to bond to the old snow surface, expect the possibility of newly formed wind slabs.  Rising temperatures and associated warming may also increase the hazard.

Friday, March 29

Temperatures will continue to warm and wind speeds increase enough that the associated hazards will still be in play.