Incoming Mango Express!!! Where it rains, watch out for loose wet snow; where it snows, watch out for storm slabs.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Big change is coming with a 'Mango Express' from the Philippines. We will shift to a more familiar warm and wet pattern on the South Coast... where umbrellas and rubber boots reign supreme!!! MONDAY: A mix of snow and rain (55mm water equivalent), with freezing rain more likely near Squamish mid-day. Winds light gusting to moderate from the southwest. Freezing level 1500m rising to 2200m and alpine temperatures to +2 Celsius. TUESDAY: Rain, and lots of it (80-120mm). Winds moderate to strong from the south. Freezing level 2700m and alpine high temperatures to +4 Celsius! WEDNESDAY: Still more rain (30-50mm). Winds moderate southwesterly. Alpine temperatures to +4 ; freezing level dropping slightly to 2100m.
Avalanche Summary
No new observed.
Snowpack Summary
We've had some sunshine and warm temperatures (as high as +6 on Grouse mountain on Saturday) through the weekend. Expect to find a lovely sun crust on solar (south) aspects. Earlier in the week, pockets of wind slab formed on exposed aspects at higher elevations. A thick crust can be found 5-10cm below the surface at treeline and below, and has limited the wind redistribution at lower elevations. The new wind slabs have already gained considerable strength but could remain reactive on steeper unsupported terrain at alpine elevations where this crust does not exist. The mid and lower snowpack are well settled and stable.
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.