The Winter Permit System is finished in Glacier National Park for the winter season and this is the last bulletin. Early starts and finishes are crucial during the warm months of the year, so if you have to get some last turns in, start by headlamp!
Weather Forecast
With increased daylight hours, there is less time in the night for temp's to drop below freezing. Incoming Spring and Summer storms will likely mean rain to mountain-tops, with the occasional colder storm dropping snow on the highest peaks.
Snowpack Summary
In May, high elevation N aspects still hold a winter snowpack with surface windslab that may be sensitive to human triggering given the right location. On all other aspects, expect temperature and sun crusts until daytime warming softens the surface. The snowpack is isothermal below these surface crusts at tree-line and below tree-line elevations.
Avalanche Summary
In Spring and early-Summer, avalanche activity can be expected during the heat of the day, during rain events, or at any time if there has not been a good overnight refreeze of the surface crust.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Loose Wet
Loose Wet avalanches are the 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. 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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.