Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Wed
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
Open full map
Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Beware of the potential to trigger various flavors of slab and loose avalanches due to the sun and the wind. With slopes that receive direct sun, expect loose wet avalanches to run, and you could trigger wide soft slabs on steep and unsupported terrain.  At higher elevations, look for wind stiffened snow and shooting cracks to clue you into wind slab danger. Make observations of snow moistness and hardness throughout the day to help determine which slopes you may want to steer around.

Lawinenprobleme

  • Loose Wet

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

    Loose wet avalanches may run on sunny slopes after just a couple hours of direct sunshine. Look for signs of wet snow instability like gloppy moist snow, and rollerballs. Steer clear of terrain traps like gullies if you find this beginning to happen. Slides could become large in larger features, and in some cases they could trigger more surprising slabs.

    On steep east to south to west aspects outside of wind affected areas you could trigger soft slabs due to warming temperatures and sun (see photo below). Pay attention to what the snow surface feels like, and look for signs of instability and shooting cracks. Avoiding very steep and unsupported slopes in the sun would be a good bet on Tuesday.

    (3/6/2023)

    Wet loose avalanches ran on steep south facing aspects on the west side of the pass on Monday.

    Photo: Josh Hirshberg

  • Wind Slabs

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

    Identify the most likely areas to hold stiffer slabs as you gain elevation. You can use a ski pole or quick hand pits to feel for deeper, stiffer drifts of snow. Steer around areas of convexities and pillowed drifts on steep, open or unsupported slopes. If you observe any signs of cracking, then back off from entering steep slopes nearby.

    Shallow, actively forming soft slabs may be reactive during the day, but it's the chance of triggering a large old wind slab that is more concerning. Avalanches could be larger and easier to trigger above treeline, where old stiff wind slabs may still prove reactive to the weight of a person or snowmobile. Pay close attention to any terrain features that appear loaded by the wind. Both easterly and westerly winds have been drifting snow over the past week, so you could find them all around the compass. 

    (3/3/2023)

    A natural slab avalanche occurred in the recent snow Friday afternoon on a leeward and sun-exposed slope. Highlands Bowl, SE, 5,600ft

    Photo: Stevens Pass Ski Patrol

Avalanche Discussion

Josh found that a small wet loose avalanche cycle had occurred on the west side of the pass on Monday (see photo below). More sun may shine just west of the pass on Tuesday, so more of these slides could occur. The more interesting slide he found was a fairly widely propagating slab on a SSW aspect at 4,700ft below the Skyline rd. This slide appears to have been remotely triggered, and the sun may have played a role increasing the cohesion of the surface snow. It may be prudent to dig quick profiles or hand pits to assess how the soft snow is bonding to recent sun crusts on solar aspects.

Last weekend was active with generall small, but reactive and natural avalanches. On Sunday, a rider triggered a small slab avalanche on a leeward slope in Highlands Bowl. On Jim Hill riders reported freshly formed wind slabs in specific terrain affected by east wind. Small slabs were very reactive on West aspects in Wenatchee Bowl on that day. 

Last Tuesday the 28th, two larger avalanches were triggered that appear to have run on a more deeply buried crust from Valentines Day. One of these was a large explosive trigger (West at 4,800ft), and another was the third rider on the slope (A heavily wind loaded SE aspect at 5,600ft). These slides were sold D2's, and 2-3ft deep. We haven't received more recent reports of avalanches on this layer, and snowpack tests have generally showed that layers in the upper snowpack are well-bonded. As always with a couple isolated deeper slab occurrences, this is still something to keep in mind, especially if traveling into higher and more wind exposed locations.

Abgedeckte Regionen