Avalanche Forecast

Issued: Mar 27th, 2018 5:11PM

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

mgrist, Avalanche Canada

South Columbia.

Give the snow time to settle and stick to conservative terrain where there is more than 25cm of new snow. Check for how the new snow is bonding to older crusts below. Reduce your exposure to sunny slopes if the sun makes an appearance.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

We're looking at unsettled weather with cooling temperatures until the next system arrives on Friday.WEDNESDAY: Mainly sunny with some cloudy periods and isolated flurries. Moderate west winds 20-50 Km/hr. Freezing level to 1500 metres with alpine high temperatures around -5. THURSDAY: Cloudy with sunny periods and flurries in the afternoon. Winds becoming light westerly. Freezing level dropping to 1200 metres with alpine high temperatures of -6.FRIDAY: Cloudy with flurries (5-10cm snow). Light north / west winds. Freezing level 1000 metres with alpine high temperatures around -7.

Avalanche Summary

A widespread natural avalanche cycle to size 2.5 was reported on Tuesday, all aspects at tree line and in the alpine. On Monday, backcountry skiers triggered a size 2 wind slab near the Asulkan cabin on a northeast aspect near 2050m. The slab's thickness varied from 40-60cm. See the MIN report for more details.On Sunday several natural and skier-triggered storm and wind slabs to size 2 were reported, on southeast through northeast aspects between 1900m and 2600m. Some ran on the March 18th layer, buried 25cm in that location.On Saturday we received reports of several wind slabs and storm slabs to size 2.5, mostly on northerly aspects above 2200m. Also on Saturday, a wet loose size 1.5 avalanche injured a skier in Glacier National Park on a west aspect near 2000m.

Snowpack Summary

New amounts of (heavy) snow varied widely on Tuesday, ranging from 7 to 36 cm (with an average of about 17cm). Winds have been moderate to strong southerly with gusts to 70 Km/hr reported. Wind slabs from late last week (thanks to south / east winds) remained reactive throughout the weekend on immediate lee features and steep roll-overs in exposed locations. New snow amounts taper with elevation and below 1900 m, reduced accumulations have buried a supportive crust on all aspectsIsolated pockets of surface hoar (buried March 18th) have been reported between old storm snow layers on shaded aspects at higher elevations and may be found approximately 50-70 cm below the surface. Deeper persistent weak layers from January and December are generally considered dormant, but could wake up with a surface avalanche stepping down, large cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets.

Problems

Storm Slabs

Storm slabs are expected to remain touchy, especially in areas that saw more than 30cm of new snow into Tuesday. South and west aspects could be tricky due to buried sun crusts which could act as a good sliding layer.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Loose Wet

Full sun on fresh snow is a recipe for avalanches. Watch for intervals of solar exposure to destabilize slabs as well as promote loose wet avalanche conditions on steeper, sun-exposed slopes.

Avoid exposure to sunny slopes.Watch for signs the snow is moistening, such as pin wheeling and point releases below cliffs.Watch for terrain traps where small amounts of snow will acumulate into deep deposits.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Mar 28th, 2018 2:00PM