Bollettino valanghe

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The wet avalanche problem from last week has been put on hold thanks to cooler temperatures. Loose, dry snow still exists on the surface from last Thursday’s storm. That snow was transported by moderate winds over the weekend which has formed new wind slabs on leeward slopes. The wind has primarily been out of the Southwest and shifts to the Northeast today, so you can expect to see the new wind slabs on many aspects. Human-triggered avalanches are possible in these areas. Be sure to evaluate the snow on leeward slopes carefully.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Moderate SW winds have transported loose snow on to Leeward slopes over the past 3 days. Winds will shift to be out of the North later today.  The loose snow is sitting on a supportable crust which was formed last week by all of the rain.  The crust is  a good sliding surface for the wind slabs.  The loose snow has packed into wind slabs on primarily N and E facing slopes. The most likely area to trigger an avalanche in the wind slabs would be on steep open faces on the Leeward side of ridge lines. 

    If you look closely you can see signs of old wet avalanches as well as wind slab avalanches. There signs of old avalanches in many areas, above treeline, right now.

    Flattop Mountain, Selkirk Mountains

Avalanche Discussion

The snowpack is becoming increasingly complex these days. The sun and recent temperature swings have created a variable snowpack with big differences depending on your aspect and elevation.

Elevation – The snow is starting to melt out in the valleys and lower parts of mountain drainages. Yesterday, we went up the Pack River and found that the snow was much thinner than a week ago. It has become very “spring like” at lower elevations. As spring settles in, we’ll see more firm, frozen, crusty snow in the mornings and soft, punchy snow in the afternoons. This normal springtime process can drastically change the avalanche hazard as the pendulum swings between frozen and melting. The longer the snowpack is in melt phase, the greater the avalanche danger. As winter makes its way out, we’ll see this diurnal temperature pattern start to happen at higher elevations. For the time being, higher elevations have more of a mid-winter snowpack.

Aspect - Snow and avalanche conditions are very different right now on different aspects. South aspects are starting to melt and show signs of recent avalanches from the last warm spell. North aspects are still cold and insulated. They haven’t seen the effect from the sun, but they have seen the effect of recent wind loading. Even though north slopes are where you’re going to find the best snow, it’s also the aspect where the new wind slabs are hiding. If you can manage the wind slab problem, skiing or riding on north-facing slopes will be the best.

Our goal at IPAC is to provide you with the best information as frequently as possible. One of our dreams is to grow IPAC into a Level 1 Avalanche Center where we could put out forecasts like this every day to help provide you with more information for decision-making. We believe this would be especially helpful during times such as these where conditions can change very quickly. Please support us so we can grow IPAC and provide more information to you. A great place to start would be becoming a member of IPAC. That support goes a long way! Check out idahopanhandleavalanche.org for more information. Have a great day and enjoy the sunshine!

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