Avalanche Forecast

Issued: Mar 29th, 2019 5:15PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Loose Wet and Wind Slabs.

shorton, Avalanche Canada

Purcells.

Cooler cloudy weather is approaching, but the danger will still be moderate during the heat of the day.

Summary

Confidence

Weather Forecast

FRIDAY NIGHT: Partly cloudy. Light southwest wind. Alpine temperatures drop to -5 C.SATURDAY: A mix of sun and cloud with cloud increasing over the day. Light west wind. Alpine high temperatures around 0 C with freezing level to 2000 m.SUNDAY: Mainly cloudy with isolated flurries in the afternoon and 5-10 cm of snow overnight. Light southwest wind. Alpine high temperatures around -2 C with freezing level to 1800 m.MONDAY: Light flurries continue throughout the day. Light northeast wind. Alpine high temperatures around -2 C with freezing level to 1800 m.

Avalanche Summary

Minimal avalanche activity has been reported in the Purcells over the past couple days. One small naturally-triggered wind slab was observed on a northeast alpine slope on Thursday. Looking forward, expect continuing warm, sunny weather to ramp up loose wet avalanche problems with each day's warming cycle.

Snowpack Summary

Variable new snow amounts of about 5 to 25 cm from a storm earlier in the week buried a crust in most areas above 1500 m. Below this elevation it buried variably moist or crusty surfaces. Precipitation fell as rain below about 1100 m. The snowpack below about 1500 m has been disappearing rapidly under the influence of warm temperatures, strong sunshine, and rain. The chance of loose wet avalanches increases each day as these factors break down surface crusts and bring snow to its melting point.The mid snowpack is generally consolidated and strong, but exceptions may exist on north aspects above 2000 m, where a layer of faceted grains may still be preserved beneath 40 to 60 cm of hard wind-affected snow.The base of the snowpack is composed of weak faceted snow which may coexist with a melt-freeze crust. Only one very large persistent slab was reported to have failed at this layer during last week's warming event.

Problems

Loose Wet

A springtime regime of daily warm temperatures and sunshine will tend to destabilize surface snow each day, especially on steep, sunny slopes. Larger avalanches become possible during peak warming.

This problem may affect shaded aspects where air temperatures exceed 0 degrees.Start and finish early to reduce your exposure to avalanche terrain during the heat of the day.Avoid exposure to terrain traps, where the consequences of a small avalanche could be serious.

Aspects: East, South East, South, South West, West.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Wind Slabs

Lingering slabs from Tuesday's storm may remain reactive to human triggers on Friday. This problem is likely to become increasingly confined to steeper, wind loaded slopes at ridgecrest.

Wind slab danger varies over the region. Increase caution in areas with 15 or more cm of recent snowUse ridges or ribs to avoid pockets of wind loaded snow.Be careful around wind loaded pockets near ridge crests and roll-overs.

Aspects: North, North East, East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Mar 30th, 2019 2:00PM