Though we are not completely into spring snowpack conditions, solar radiation and daytime heating will be the big factors on Sunday. It is time to start early and finish early. Don't underestimate the de-stabilizing affects of the April sun.
Summary
Confidence
Good - Timing or intensity of solar radiation is uncertain
Weather Forecast
A sunny and relatively calm morning is expected on Sunday with intense solar radiation and rising temperatures. Convective flurries are likely in the afternoon.
Avalanche Summary
A few loose dry slides were observed today on steep N and E aspects up to size 2.0. Also, some small loose wet avalanches occurred on sunny slopes in the afternoon. A very large slide (size 3.5) occurred sometime on Friday in the Tyrwhitt region. This avalanche failed on both the February surface hoar and the basal facets and destroyed approximately 2 Ha of mature forest. It is quite possible that we will see large avalanches as we transition to spring due to a deeper than average snowpack and two concerning deeply buried weak layers.
Snowpack Summary
No new snow overnight, but lots of low density snow is available for transport. Wind loading is occurring at alpine and treeline elevations on lee slopes. On E, S and W aspects crusts are forming each evening and melting each day. The extent of melting is related to the amount of radiation and the air temperatures. Dry snow remains on N aspects above 1900m in most locations. The snowpack is settling. The deeply buried February surface hoar and basal facets are sporadically active in large natural avalanche events, including some triggered by cornice failures.