Freezing levels are expected to rise to 3000 m for the next two days. Treeline temperatures steady near +6 accompanied by intense solar radiation and limited re-freeze. Expect danger ratings to remain elevated through the forecast period.
Confidence
Fair - Intensity of incoming weather is uncertain on Thursday
Weather Forecast
The beautiful weather we've been seeing over the past few days will start to change as a dominating upper ridge begins to break down, and turn to a warm Southerly flow. A series of systems caught in this flow will affect the region through to Friday. Tuesday: Continued sunny, cloudless skies with light ridgetop winds from the SW. Freezing levels could reach 3000 m. A temperature inversion may redevelop bringing warmer alpine temperatures through the night. Treeline temperatures steady near +5 C. Wednesday: A mix of sun and cloud with possible afternoon rain showers. Treeline temperatures near +10, with freezing levels 3000 m. Thursday: Possible 20 mm of precipitation (mix rain and snow) through the day, with freezing levels falling to 1500 m. Ridgetop winds moderate from the West.
Avalanche Summary
No recent avalanche activity has been reported. On Friday in the Fernie area a skier triggered a size 1.5 avalanche with a 20 cm crown on an E facing slope at 2000 m Friday. Some loose snow activity on a SE facing slope was also reported, but, there is surprisingly little avalanche activity in the region currently.
Snowpack Summary
Spring like weather, and conditions have promoted settlement and bonding of last week's storm snow over the April 4th melt/freeze crust, producing little avalanche activity. Below this a cohesive slab 60-120 cm (depending on the drainage) sits on the March 27th interface. Our field team was out in the region Saturday; they were able to find the March 27th interface down around 90cm but test profiles did not produce any results on this layer. Large cornices loom over many lee slopes. Glide cracks are a concern, be sure to give them a wide berth as they are very sensitive and could fail at any moment.
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.
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.
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.