Boletín de aludes

East Slopes North

Northwest Avalanche Center
Ver en el mapa

Peligro de aludes

Fri
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
Open full map
Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Continued E winds may produce cross-loading and pillow-like drifts you can trigger in exposed terrain at all elevations. Morning sunshine may destabilize steep southerly slopes to generate small natural wet or dry snow avalanches. Elsewhere, you will need to manage dry sluffs in steep, rocky terrain features.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    Light to moderate east winds formed slabs over the past three days and may continue to be strong enough to transport snow on Thursday. Washington pass should have 10-12" of gradually settling snow above the 4/8 crust while Harts pass may have 4-6" with generally lighter winds. With more snow to transport at Washington Pass, expect slabs to be a bit larger in this area, potentially to size 1.5.  Observers encountered stronger winds at lower elevations at Stevens Pass on Wednesday, and this may also be true for the East North zone. Therefore, watch for cross-loaded features even in terrain even below the treeline or lens-shaped and textured snow near ridgelines. Remember that with unusual wind directs come atypical loading patterns with slabs focused more on the W side of the compass.  If you observe shooting cracks in drifted snow, stay off of leeward slopes 35 degrees and steeper. Cornices may be fragile from recent growth, and could break under the weight of a person. 

    Example: Use visual clues to help you determine where Wind Slabs may be lurking near ridgelines.

    Photo: Andy Harrington

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    It will be a fine balance between strong April sun making an appearance in the morning and cold, but moderating morning temperatures. Even 10 minutes of direct sunshine may be  enough to tip the scales and destabilize the low-density surface snow on very steep southerly aspects. These avalanches will entrain more if they become wet, potentially reaching size 1.5. Wet or sticky snow surfaces, snow shedding off rocks or cliffs, and rollerballs should all clue you into the surface destabilization trend. Consider moving toward more shaded aspects or slopes less than 35 degrees.

    Dry loose avalanches in storm snow have been common on a variety of aspects over the past few days. On shaded aspects or if the sun doesn't make an appearance, you can trigger them in very steep or extreme terrain at all elevations and aspects. Use extra caution near slopes with terrain traps such as trees, gullies, or rocks.  In these locations, small slides could result in injury or worse.  

    Both wet and dry loose avalanches will increase in size as snow amounts increase above the 4/8 crust, so keep tabs on the snow depth as you travel through the terrain.

    Example: Rapid transition of cold surface snow on steep southerly slopes producing shallow wet loose avalanches.

    Photo: Sam Luthy

Avalanche Discussion

Easterly flow and upslope snow have favored Washington Pass. WSDOT forecasters reported 8" of new snow on Washington Pass on Tuesday and the snow stake indicates that perhaps another 4-6" fell through early Wednesday with cloud cover keeping snow surfaces cool most of the day.  Light accumulations of snow remain possible on Thursday, primarily with afternoon convection. Plan alternative options or escape routes if visibility above the treeline deteriorates with the weather.

Information and observations are limited. Access to snow-covered slopes has become difficult in many parts of the zone. Be prepared to make your own observations and assessments. If you see conditions different from what we describe, defer to lower-angle and simpler terrain. The North Cascades Highway SR 20 is currently gated at Silverstar, though the road is plowed further west. Until the road opens, the WA State DOT allows recreational access on the North Cascades Highway near Washington Pass from Friday-Sunday. With road clearing operations underway midweek and other professional operations inactive, your observations are needed. If you're out in the mountains, let us know what you see. 

Regiones cubiertas