Avalanche Forecast

Explosives control in a permanently closed area at Marmot Basin on Sunday reported triggering a size 2 persistent slab, stepping down to basal weaknesses.

A size 2 skier accidental triggered deep persistent slab avalanche was reported on the regular approach to the north glacier on Mt. Athabasca on Thursday.

Natural activity has tapered off but still requires vigilance and careful assessments.

Don't forget to post avalanche observations to the MIN.

New snow is forecasted for overnight Sunday, up to 5-10cm, expect rain below freezing level. Upper snowpack consists of 20cm of snow from the previous storm sitting on multiple crusts up to 2400m. Snow pit tests are showing results in the weak facet crystals below these crusts on south aspects. The snowpack below 1800m is in a daily melt-freeze cycle. The mid-pack above this elevation consists of multiple layers of sun crusts or facets. Depth hoar and basal facets make up the base of the snowpack.

Sunday night will see rising freezing levels to 2300m and flurries producing up to 7 cm at higher elevations and rain below. Ridge wind from the southwest (20 km/h gusting to 55 km/h).

For Monday expect a mix of sun and cloud and a alpine high of -8 °C. Ridge wind from the southwest (20 km/h gusting to 50 km/h). Freezing level will be at valley bottom.

Tuesday will be another day of cloudy with sunny period conditions. Alpine temperatures are forecasted to be a low of -11 °C and high of -5 °C. Ridge wind will be from the southwest (10-25 km/h) and freezing level at 1600 metres.

• Keep in mind that human triggering potential persists as natural avalanching tapers off.
• Stay off recently wind loaded slopes until they have had a chance to stabilize.
• Remember that in the spring strong solar radiation and warm temperatures can weaken the snow in a matter of minutes.
• In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.