Avalanche Forecast

Issued: Mar 26th, 2016 8:53AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs, Cornices and Persistent Slabs.

Avalanche Canada bcorrigan, Avalanche Canada

Use caution in wind affected terrain, and give cornices and their run-outs a large amount of respect.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

The Northwest Inland will see light precipitation through the weekend in advance of a ridge of high pressure that will bring clear skies and warm temperatures. TODAY: Freezing level dropped to around 700m last night but should rise to around 1200 m during the day. 5 to 10 cm of snow in the forecast, light to moderate south/southwest winds. SUNDAY: Freezing level dropping to 700 m overnight, then rising to 1200 m during the day. 1 to 5 cm of snow, with light winds from the southwest. MONDAY: Freezing level dropping to 600 m overnight, then beginning to rise to 1100 m by midnight. Light west winds, but no precipitation in the forecast for Monday.  TUESDAY: Will start with the freezing level around 900 m, then begin a slow but steady rise to end the day around 2500 m. No precipitation on Tuesday and light to moderate west winds.

Avalanche Summary

Reports from yesterday tell of moist snow, loose-wet avalanches up to size 1.5 on solar aspects, and in the north of the region, a natural size 2 avalanche was observed on north facing terrain at 2100 m. It is believed to have been the new storm snow running on March 23rd surface hoar. The slab was 25 cm deep and started on a 40 slope.

Snowpack Summary

In the last 48 hours 5 to 10 cm of snow has fallen accompanied by moderate to strong southerly winds. At treeline and in the alpine small wind slabs are expected to have formed. These wind slabs overlie a variety of surfaces which include a hard crust on solar aspects above 1300 m, moist or refrozen snow on all aspects below 1300 m, and settled wind slabs in exposed high elevation terrain. A layer of surface hoar or melt-freeze crust buried on March 3 is down 50-80 cm and has been on the radar of professionals in the mountains north of Stewart. A more widespread crust/facet layer buried in early February can now be found down over a metre. Both of these deeper layers have become less likely to trigger, but have the potential for large avalanches especially with a large trigger such as a cornice fall. I'd be increasingly cautious during periods of warming and intense solar radiation.

Problems

Wind Slabs

An icon showing Wind Slabs
New snow with moderate west winds will build wind slabs in lee terrain at tree line and above.
Avoid cross loaded slopes at or above treeline.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be cautious as you transition into wind affected terrain. >

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices
New snow with moderate west winds will continue to build cornices. Rising temperatures will make them weak.
Pay attention to overhead hazards like cornices.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 5

Persistent Slabs

An icon showing Persistent Slabs
Still on everyone's radar in the Northwest Coastal region.  A large trigger such as a cornice might reawaken this sleeping beast..
Conditions have improved, but be mindful that persistent instabilities are still present.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Mar 27th, 2016 2:00PM

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