Regions
Northwest Coastal.
Monday is expected to dawn warm/cloudy and will likely finish cool/sunny. You need to stay alert and make sure your travel plans are in-tune with the rapidly changing conditions if you're headed to the mountains Monday.
Weather Forecast
Winter and summer will continue to battle it out Monday before a sustained warm-up begins Tuesday morning. MONDAY: Overcast skies initially, clearing late in the afternoon, freezing level starting near 2500m, lowering to around 1200m by the afternoon, strong to extreme south/southwest wind, 2 to 15 mm of precipitation expected. TUESDAY: Scattered cloud cover, freezing level beginning around 800m, climbing to about 2500m in the afternoon, light southwest at treeline, strong southwest wind at ridge top, no significant precipitation expected. WEDNESDAY: Clear skies at dawn, cloud cover building through the day, freezing level holding around 2000m, light to moderate southwest wind, no precipitation expected.
Avalanche Summary
On Saturday, reported avalanche activity was limited to control work induced wind slabs to size 1.5 on a north facing piece of terrain around 1500m. Remember that we have very few eyes & ears still in the mountains at this time.
Snowpack Summary
10 to 30 cm of new storm snow has fallen above 1500m in the last last few days. The wind has primarily been out of the south during the storm, which has likely formed fresh wind slabs and created new cornice growth. The storm snow has buried a widespread melt-freeze crust which was thought to exist almost everywhere, the exception may be high elevation north facing terrain. Any old layers in the midpack or at the ground are dormant for now, and the snowpack may just gracefully melt away. However, these layers have the potential to wake up; the hottest weather of the year is expected over the next few days which might test almost forgotten layers.
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.
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.
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.