Avalanche Forecast
Regions: North Columbia.
Additional snow, wind, and warm temperatures on Thursday night may form touchy storm slabs reactive to human triggers at treeline and above.
Confidence
Moderate - Freezing levels are uncertain
Weather Forecast
THURSDAY NIGHT: Rain (snow above roughly 2000 m.); 10-20 mm / Strong, southwesterly winds / Alpine low -1 C / Freezing level 2200 m.
FRIDAY: Rain (snow above roughly 1500 m.); 5-10 mm / Moderate, southwesterly winds / Alpine high -3 C / Freezing level 1700 m.
SATURDAY: Sunny / Light, northwesterly winds / Alpine high -2 C / Freezing level 1800 m.
SUNDAY: Sunny / Light, northwesterly winds / Alpine high -1 C / Freezing level 2100 m.
Avalanche Summary
No new avalanches were reported on Wednesday. However, avalanche activity is expected to increase on Friday with the forecast rain/snow and strong winds.
On Tuesday, a natural size 2.5 persistent slab avalanche was reported on a west aspect at 2750 m. Additionally, a skier triggered size 2 storm slab avalanche was reported on an east aspect at 2700 m.
On Monday, a skier remotely triggered a size 2 storm slab from 10 m. away on a steep north facing feature in the alpine that was 20-30 cm. deep.
Snowpack Summary
New snow/rain on Thursday is adding to the 20-40 cm recent snow which overlies a crust everywhere except high elevation, north facing terrain where preserved surface hoar (weak, feathery crystals) may be present in isolated locations. A similar layer buried in early April is down 40-50 cm. Smaller storm slab avalanches may step down to one of these deeper weak layers.
Below treeline, snow is disappearing rapidly.
Avalanche Problems
Storm Slabs
Additional snow, wind, and warm temperatures on Thursday night may form touchy storm slabs reactive to human triggers at treeline and above.
- Pay attention to changing conditions with elevation/aspect.
- Use small slopes without consequence to test the bond of the recent snow.
- Minimize overhead exposure during periods of heavy loading from rain/snow and wind.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2.5
Loose Wet
Forecast rain may initiate a loose wet avalanche cycle.
- Avoid terrain traps such as cliffs and gullies that increase the consequence of small avalanches.
- A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood: Likely
Expected Size: 1 - 2