Avalanche Forecast

There may be enough sun and the warm temperatures for isolated loose wet avalanches on steep sunny slopes. They may even run naturally. These avalanches will be small and easy to predict. Building clouds should put an end to these avalanches for the latter half of the day. Don't linger on or under steep, sun-exposed slopes. Rollerballs and soft, moist snow surfaces are signs that loose wet conditions are building. If you're traveling in terrain 40 degrees and steeper, you could also trigger small loose dry avalanches on shaded aspects.

Release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. They generally move slowly, but can contain enough mass to cause significant damage to trees, cars or buildings. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Travel when the snow surface is colder and stronger. Plan your trips to avoid crossing on or under very steep slopes in the afternoon. Move to colder, shadier slopes once the snow surface turns slushly. Avoid steep, sunlit slopes above terrain traps, cliffs areas and long sustained steep pitches.

Several loose wet avalanches, and lots of pinwheels and roller balls.

Loose wet avalanches occur where water is running through the snowpack, and release at or below the trigger point. Avoid terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.

A crust from early February associated with facets above and below is still a concern in some areas. At lower elevations, the snowpack is shallow and weak on shaded aspects. In the foothills, these facets can be found near the ground beneath the snow from February and the crust has completely decomposed. Persistent slabs are a concern on isolated, shaded slopes where stronger snow may rest over facets. This structure is more concerning than at upper elevations, where aside from the recent storm snow, the snowpack is generally deep and strong. Persistent slabs are unlikely at upper elevations and in the western portion of the zone.

If you find signs of instability such as cracking and collapsing, avoid steep slopes nearby. Terrain management becomes key. Stick to well-supported slopes and avoid places where firm slabs look to exist near shallow rocky zones. Travel one at a time from well defined safe zones when moving through avalanche terrain.

Release of a cohesive layer of soft to hard snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slabs.

The best ways to manage the risk from Persistent Slabs is to make conservative terrain choices. They can be triggered by light loads and weeks after the last storm. The slabs often propagate in surprising and unpredictable ways. This makes this problem difficult to predict and manage and requires a wide safety buffer to handle the uncertainty.

This Persistent Slab was triggered remotely, failed on a layer of faceted snow in the middle of the snowpack, and crossed several terrain features.

Persistent slabs can be triggered by light loads and weeks after the last storm. You can trigger them remotely and they often propagate across and beyond terrain features that would otherwise confine wind and storm slabs. Give yourself a wide safety buffer to handle the uncertainty.