Avalanche Forecast

Archived

Apr 14th, 2019–Apr 15th, 2019

Alpine

Natural avalanches possible, human triggered probable.

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Lizard-Flathead.

Winter is going out with a bang after producing 30 cm of storm snow Saturday night. Rising temperatures and the strong April sun are expected to produce natural avalanche activity over the next few days.

Confidence

Moderate -

Weather Forecast

Well, we got "Fernied" Saturday night! This week ushers in a rather slack pattern for the Lizard Range with the big story being the steadily rising freezing level. It doesn't look like we'll get any significant precipitation this week. Enjoy the new snow before it really starts to warm up!SUNDAY NIGHT: Freezing level around 1000 m, moderate west/southwest wind, 1 to 5 cm of snow possible. MONDAY: Scattered cloud cover, freezing level rising to around 1500 m, light variable wind, trace of snow possible. TUESDAY: Scattered cloud cover clearing to just a few clouds around lunch, freezing level rising to around 2100 m, light variable wind, no significant snowfall expected. WEDNESDAY: Scattered cloud cover, freezing level rising to around 2200 m, moderate to strong west wind, no significant snowfall expected.

Avalanche Summary

A natural avalanche cycle occurred Saturday night, the highlights were storm slabs up to size 2 on northeast facing alpine terrain around 1700 m. A natural cornice failure was observed from a north facing ridgeline which subsequently triggered a size 2.5 storm slab involving the new snow. Control work produced storm slabs to size 2.We received a great MIN report of a small storm slab from Saturday morning, and this was well before the storm really kicked into gear. On Friday small loose wet natural avalanches were reported from steep south facing terrain.

Snowpack Summary

The Fernie Factor really kicked in late Saturday into early Sunday. The region picked up about 30 cm of snow (and 53 mm of water). This snow sits above a widespread supportive crust. Steep, north facing, alpine terrain may still hold a cold, dry, snowpack where fresh storm slabs are thought to be widespread. Steep north facing terrain is also harboring a deeply buried layer of facets. Although unlikely, human triggering of persistent slabs on this layer may still be possible, especially in rocky alpine terrain with a shallow or highly variable depth snowpack. It looks like it is going to warm up this week and all the new snow will likely produce a widespread and powerful loose wet cycle. During the heat of the day, especially under direct sun, the snow surface will become moist or wet almost everywhere (except for high elevation north) and loose wet avalanches could run far.Below treeline the snowpack has melted or is isothermal.

Problems

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.

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.