Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A chance for sun could melt the new snow and cause small roller balls on steep southerly slopes. There's not enough recent snow for significant avalanche danger.  Firm and slick surfaces will make mountain travel challenging. 

Avalanche Discussion

While avalanche conditions are generally safe, firm surfaces will present the potential for uncontrolled falls on steep slopes. Plan accordingly and bring appropriate travel equipment to grip on hard, frozen snow surfaces. The skiff of snow that accumulated may slide easily on steep slopes. Clearing could bring roller balls on sun-exposed slopes. Winds may form very small drifts at upper elevations. Any poorly bonded new snow won't be deep enough to present an avalanche hazard.

Warm temperatures in early February drove multiple rounds of wet avalanches. NWAC forecasters observed a D2 wet loose avalanche that ran 1000ft on a SSE aspect of Lichtenberg Mtn on February 12th (see photos). Some of the larger slides that are visible in the mountains likely occurred with a rain event on February 9th. 

Sun-exposed southeast through southwest slopes have seen a significant transition to melt forms in the upper snowpack. What was the late January weak layer is now a mass of stout melt forms. The weak layer can still be found on some northerly and shaded slopes, though avalanches on it are unlikely, at best. Some recent profile locations have revealed that the layer is well-rounded and hard. However, the weak layer characteristics previously varied significantly throughout the terrain.  While the layer never produced an avalanche cycle in this zone, it was the source of collapsing and signs of instability.  Observers reported sudden test results as recently as Feb 8th. Natural slab avalanches were reported over the weekend on this layer in both East North and West North zones, where it's been more problematic.

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