Avalanche Forecast

Issued: Jan 4th, 2017 5:55PM

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

Tim Haggarty, Parks Canada

Waterton Lakes.

Waterton Waits for West Winds.The Upper lake is half frozen and a lot of snow is still sitting around waiting for the winds to blow. Forecasts show the winds shifting to light Westerlies Thursday... lets hope they stay light as promised.

Summary

Weather Forecast

The flow shifted a bit to the NW today with minor transport visible on the high peaks and a welcome increase in temperatures arriving. As a Low off of the coast pushes its way past a stubborn arctic high over the next three days the westerly flow will intensify before shifting South with the arrival of the low Sunday with precip and warmer temps.

Snowpack Summary

Up to 20cm fell with last weekend's storm with NE winds pushing in from the Prairies. It has been cold and calm since and this snow has settled in place. Down 60 - 100 cm is a thick mid-pack layer of sugary facets. The slab properties over this layer are variable with snowpack depth and have likely weakened with recent cold temps.

Avalanche Summary

No avalanches have been observed or reported since the weekend.On Saturday, debris from several large (Size 2) slab avalanches were observed. These were all in the South-West of the park, which received the highest snowfall totals Thursday night. One Wind Slab on Mt Rowe stepped down to the December 9 Persistent Weak Layer (facets).

Confidence

Due to the number of field observations

Problems

Persistent Slabs

The weak mid-pack facet layer is widespread, but the slab over it is variable. These may be difficult to trigger but are high consequence. Avoid large uniform features, shallow trigger points, and watch for slab properties in the upper snowpack.

Avoid shallow snowpack areas where triggering is more likely.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 7th, 2017 4:00PM