Glacier National Park Avalanche Forecast
Mar 14th, 2019 8:00AM
Storm slabs may be reactive to human triggering, especially on steep solar aspects and wind-affected features.
Today, cloudy with sunny periods, an alpine high of -7*C, freezing levels rising to 1300m, light SW winds, and scattered flurries tonight. Friday will bring a mix of sun and cloud, with light/moderate W winds, alpine high of -7*C, and freezing levels rising again to 1300m. The weekend brings cloudy conditions before a big warm-up early next week.
Roughly 50cm of snow has fallen at tree-line over the last week. Moderate winds and mild temp's have created a cohesive soft slab which sits on: a sun crust on solar aspects; hard wind slab in exposed areas; and surface facets in sheltered locations. Steep solar aspects (SE through to W) now have a crust from yesterday's sunshine.
A human-triggered size 1.5 avalanche on Glacier Crest took 2 people for a short ride on a W aspect at 2100m. Numerous loose, dry natural avalanches from size 1 to 2.5 were observed yesterday in the alpine when the sun hit at full-force. SE through to W aspects all shed surface snow. Macdonald Gullies 3, 9, 10, and 11 had slabs to size 2-2.5.
45-50cm of new snow over the last week has become a cohesive soft slab in the Alpine and exposed areas at tree-line. Storm slabs may be overlying weak faceted snow, old wind slabs, or a sun crust. The bond to these old surfaces is variable.
Convex features and steep unsupported slopes will be most prone to triggering.The storm slab may be more sensitive to human triggering on solar aspects where it sits on a crust
Brief periods of intense sunshine are enough to trigger loose avalanches. This being said, northerly aspects are also prone to loose, dry avalanches with the new snow lying on facets.
Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.
Valid until: Mar 15th, 2019 8:00AM