Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Apr 24th, 2013–Apr 25th, 2013

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Glacier.

Wide variability and springtime conditions exist.  Cornices are a prime concern for avalanche triggering.  Solar radiation is expected to be strong today, so timing and route selection will be important.

Weather Forecast

Clear skies this morning giving way to overcast skies as a weak disturbance moves through late this afternoon.  Winds may keep things cool, but direct solar radiation will cause locally very warm conditions.  Another low pressure is expected for Thursday and Friday, with cool unsettled weather for the weekend.

Snowpack Summary

In the alpine, due north aspects are maintaining dry snow conditions over multiple temperature crusts.  Solar aspects have more crusts, and daytime warming is creating sticky, wet, and/or crusty conditions.  At lower elevations (below 2200m), the snowpack is largely isothermal, but overnight re-freezing provides firm travel early in the morning.

Avalanche Summary

The number of avalanche observations is dropping off, in part due to fewer people in the backcountry to report.  Cornice failures remain the biggest concern for triggering larger slab avalanches, which are mostly failing on the April 3 PWL (sun crust-surface hoar combo), down 40-80cm.  Moist avalanches will be almost certain today.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Friday

Problems

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.

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of 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 Slab.