April 7, 2014

Avalanche Danger Increasing

After about three weeks of relatively quiescent weather and over two weeks of low avalanche danger, the game has changed.  As of 9:30am this morning, it’s snowing (having recently transition from a rain/snow mix) in East Anchorage and is expected to continue through at least Tuesday morning with snowfall becoming steadier and heavier by Monday night.

Fortunately, winds picked up enough Friday-Sunday to mitigate a relatively widespread surface hoar problem.  However, scattered pockets of intact and dangerous surface hoar are expected to have survived in areas that have been the most protected/sheltered from wind and sun.  Wind-sheltered mid to upper elevation northerly aspects are suspect and should be treated with caution.

Otherwise, the old snow surface was quite variable consisting of crusts and extensively faceted snow – also weak layers or weak interfaces that are suspect and should be treated with caution.

Sporadic, light, and moist snowfall Friday-Sunday refreshed the snow surface in some areas, bonded relatively well to the old snow surface, and is expected to facilitate bonding of new snow that will fall on top of it Monday-Tuesday.  Temperatures are also expected to drop Monday-Tuesday as snowfall becomes heavier and steadier, which should provide a less dangerous “right-side up” deposit of fresh snow.  Additionally, warmer spring temperatures and resultant less dramatic temperature gradient will also bode well for relatively quick stabilization of new snow.

Nonetheless, it will be important to approach the Front Range and Eagle River area Chugach Mountains (Chugach State Park) with caution, a fresh outlook on avalanche danger, and respect for a variety of potential instability concerns.

As high pressure (sunny weather) is expected to return by midweek, expect the new snow on sun exposed slopes to wet avalanche (primarily wet loose) readily – both naturally from thinner, rockier areas of the snowpack (point releases) and via human triggered sluffing.

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