Avalanche Forecast

Tuesday night: Cloudy. Light to moderate west wind. Freezing level 800 m.

Wednesday: Cloudy. Light northwest wind. Freezing level 1000 m.

Thursday: 5-10 cm new snow. Moderate southwest wind. Freezing level 1300 m.

Friday: Mix of sun and cloud. Light southwest wind. Freezing level 1700 m.

This MIN post from Monday reports a skier triggered size 1 wind slab in the alpine, suspected to have run on surface hoar. Explosive control work conducted Monday produced size 1-1.5 storm slabs running on a crust.

30-60 cm of recent snow sits over a layer of surface hoar on north-facing (shady) aspects. There may also be areas where the surface hoar sits on a crust, which makes an excellent bed surface for avalanches. Surface hoar is an exceptionally weak layer not often seen in this region. It is expected to persist at least through the week. It is buried deep enough that it is stubborn to human triggers, but may be reactive where overlying snow depths vary due to wind.

The remainder of the snowpack is well settled. Depth varies from around 250 to 300 cm at the peaks of the North Shore mountains (1400 m) tapering rapidly with elevation to no snow below 1000 m.

• Be alert to conditions that change with aspect and elevation.
• Keep in mind that human triggering potential persists as natural avalanching tapers off.
• Avoid terrain traps such as gullies and cliffs where the consequence of any avalanche could be serious.
• Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
• Be carefull around freshly wind loaded features.
• Caution around convexities or sharp changes in terrain.