Avalanche Forecast

Archived

Feb 9th, 2019–Feb 10th, 2019

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Mt Hood.

You are likely to trigger a storm slab where recent moderate winds have stiffened snow surfaces or where settlement and sunshine consolidate the thick storm snow layer into a slab. The slab sits on heavily faceted old snow which will increase slab propagation to produce large avalanches.

Discussion

Snow and Avalanche Discussion

9-14” of storm snow fell at low density from mid-day Friday through the end of the day Saturday. The storm snow buried surface hoar or near surface facets near and below treeline or a crust BTL and on sun-affected aspects. Areas that head weak underlying snow are more likely to produce avalanches Sunday. Loose dry avalanches will continue to be a concern in very steep terrain that isn't wind affected. Keep this in mind around terrain traps; you don't want a small but fast moving avalanche to take you on an unexpecting ride into trees or over a cliff.

Snowpack Discussion

Regional Synopsis coming soon.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.