February 28, 2015

Weekend Avalanche Outlook

The avalanche danger in Chugach State Park this weekend remains elevated due to loading from snow and wind during last weekend’s warm and wet storm, more recent wind loading that began mid day Friday, and forecast new snow Saturday.

It will be important to remain mindful of serious wind slab and persistent slab concerns Sunday, as it is forecast to be a beautiful day; play safe: be prudent and don’t let the sunshine and fresh snow lure you into a potentially dangerous situation.

Avalanche Concerns:





Click here to learn more about wind slabs

Observations this week have raised concern about touchy wind slabs in steep (35+ degree), upper elevation (3000’+) leeward (primarily northerly) terrain across Chugach State Park.  Check out those observations via the drop-down tab above for more information.

These wind slabs are likely to be hidden by forecast new snow Saturday afternoon-evening, have likely become larger-deeper due to moderate SE winds having continued the wind loading process since mid day Friday, and may become even more dangerous as they become denser and more stubborn to trigger: luring one further onto the slab before they release and releasing above the trigger making escape more difficult.

Be mindful of the clues as to these wind slabs’ distribution: cracking, collapsing and whumphing, areas of denser-deeper snow (especially if it has a hollow feel), pluming or drifting snow (indicating wind direction and where snow is being redistributed to/from).





Click here to learn more about persistent slabs

The Chugach State Park snowpack remains extremely thin for this time of year, and is extensively faceted with the number of persistent weak layers varying depending on the depth of the snowpack.  Any area with a snowpack seems to be hosting persistent weak layers, with the deeper areas being host to more of them.  Crust-facet combos are the primary concern.

Persistent weak layers and persistent slabs may be further stressed and more sensitive this weekend due to additional loading from wind (since mid day Friday) and new snow (forecast for Saturday).

You will need to be diligent to adequately assess this more elusive hazard by digging snowpits, assessing snowpack stratigraphy (analyzing the layers), and conducting stability tests.

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