High pressure over the Southwest increases the warming trend today. Hourly forecasts across our area show rapid warming beginning mid-morning and continuing through the afternoon at all elevations. Snow levels are set to rise to 9000’ by evening. Typical spring thaw instabilities are expected to accompany the balmy weather. As the sun rises it will heat E aspects first, then S, then W by afternoon. Lower elevations will heat up before higher elevations. Wet snow melting at the surface will lose cohesion and become less and less stable as it warms through. Rollerballs coming down the slope around you and sinking into wet snow above your boot tops are signs of increasingly unstable conditions. The daily melt cycle has repeated itself already at middle and lower elevations on more southerly slopes. Higher elevation E-S-W aspects, and low elevation NE and NW aspects, may see more warming today than they have before. Specific terrain features that increase the risk of deep thawing include areas that will receive and retain more solar radiation. Gullies, bowls, and cirques will warm more than open slopes. Steep rocky terrain or slopes with tree cover are suspect. Areas with shallow, low density snow cover often become unstable first.
Even small loose wet avalanches can be dangerous if they carry you into hazardous terrain. They are heavy and hard to escape. And smaller point releases often indicate that larger and more dangerous wet slides are becoming possible. The good news is that you can avoid the problem all together. Timing is everything. Plan to be off of steep sunny slopes before they warm too deeply. Riding slush is no fun anyhow, so why risk it?
