The snowpack in Yoho is generally stronger than the snowpack further east, towards Banff. Areas like Mt. Field and the west side of the Wapta have a deeper and mostly well-consolidated snowpack. With the clear skies and sun this week, watch carefully for signs of instability as the day warms up.
Three persistent weak layers formed in January are down 60-120 cm. Buried sun crusts on steep solar slopes present the greatest concern for triggering, however, weak facets and isolated surface hoar can be found on the same interfaces on shaded aspects.
Clear skies and sunshine will produce wet avalanches on sun-exposed slopes late in the day. Rocky areas often increase this heating and low elevations may also be susceptible to this problem on Tuesday.
The weak depth hoar at the bottom of the snowpack inspires little confidence. We have seen increased activity on this layer through the week in most areas of the forecast region with the exception of the deeper snowpack areas around Little Yoho. Give careful consideration to the slopes overhead as large avalanches may run well into the runout zone or into lower-angle terrain. Avoid big terrain features and be especially cautious in thin or rocky areas, where triggering is more likely.
A ridge of high pressure is dominating the weather picture until mid-week. Expect a few clouds in southern areas, but otherwise clear skies, light winds and freezing levels reaching 1800 m. Expect the sun to pack quite a punch in sheltered areas.
There was a late-day loose wet avalanche cycle on Sunday, with temperatures reaching up to 11 degrees in the valley bottom. As of 4 pm on Monday, no new avalanches have been observed. We continue to expect deep persistent avalanches with almost any change in the weather, but so far this week no significant new ones have been reported.
Above 1600 m the surface is 10-25 cm of soft, settled snow with minimal wind effect. Suncrusts are forming on steep solar slopes and are more widespread below 1400 m. The middle of the snowpack holds several crust layers that continue to produce avalanches, and the base of the snowpack is weak facets that appear their strongest in deep snowpacks such as in Little Yoho.
