Lawinenlagebericht

East Slopes North

Northwest Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

A cold northeast wind is drifting a substantial amount of snow around. Wind slabs may be easily triggered as they rest over weak, sugary snow and have a firm crust as a potential bedsurface. Stick to well supported and lower angle slopes, especially if you observe signs of instability like shooting cracks or the snow feels slabby and hollow.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    We're only expecting an inch or two of new snow in the zone, but the wind is the bigger story. Snow has been drifting readily since Wednesday when a cold NE wind arrived. Snow surfaces likely consist of sharp, faceted grains and now hard, wind packed snow. This is a classic setup for touchy wind slabs as winds continue to form slabs. If you find fresh drifts that create shooting cracks when provoked, steer around pillows and drifts on steep slopes. 

    Look for wind rippled and stiffer snow surfaces, these will help pinpoint where you could trigger avalanches.  Areas near ridgelines or pronounced ribs may be especially prone to drifting. Slopes beneath large cliffs also tend to harbor slabs, as loose snow spindrifts off and accumulates below. You can use small test slopes to check how easily the snow fractures. You can also choose slopes less than 30 degrees or look for wind-sheltered terrain to avoid this problem.

    (2/9/2024)

    Skiers triggered a very small (6" deep) windslab avalanche that ran on the 1/31 crust. Copper Creek, SE, 7200ft

    Photo: Harry Keane

Avalanche Discussion

An incoming storm is bringing cold temperatures and mostly wind to the zone. A few inches of snow are possible, but its really the wind that'll be the driver of our avalanche conditions on Thursday. Observers have been reporting small ski triggered wind slab avalanches from alpine terrain every day for a handful of days. The increasing northerly winds may create stiffer slabs, and reactive slabs on those windward aspects. On slopes that receive direct sun, expect a thin breakable crust. Steep sheltered slopes hold potential for loose dry sluffing, as was reported in adjacent west North zone (Ruby Mountain) on Wednesday. 

Last weekend, forecasters traveled in the mountains north of Mazama and Winthrop. They found a stout but shallower snowpack, with the typical 1/31 crust in the upper snowpack. At upper elevations, a thin layer of larger facets was on the ground. The hard overlying slabs and crust should keep the facets from being a concern for avalanches. Recent storm totals on the 1/31 crust are similar, if slightly less than near Washington Pass above 6,000ft. Favored upper elevation terrain held as much as 1.5' (45cm) over the crust, while lower elevations had as little as 2". Small facets were found in some locations just above the 1/31 crust, and we'd expect that these are more pronounced by now.

Snowpack information is limited outside of the Highway 20 corridor, including Harts Pass, the Chelan Sawtooths, and near and east of Mazama. If you're traveling in these areas, let us know what you find by submitting an observation.

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