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.
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
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.