The small pulses of snowfall forecast for the Central Mountains during the early part of this week are not likely to drastically affect the overall avalanche danger. Today's storm is expected to bring 3 to 5 inches of light and fluffy snow to most of the Central Mountains with light winds. As west winds increase tomorrow, you can expect to find small, wind-slabs developing on easterly facing slopes. The current conditions near the surface are worth noting before they become buried. Recently, periods of cold and clear conditions have been helping to form near surface facets on the shady aspects. The lengthening daylight hours are building crusts on the sunny slopes. Generally speaking, new snow doesn’t typically bond well with crusts or near surface facets.
The upper snowpack generally consists of the recent, lower density snow resting on top of the Valentines day storm and the early February storm. Depending on location, the early February layer is resting on buried facets, crusts and on the Grand Mesa, a thin graupel layer. We are finding that many of the large avalanches that occurred during this last cycle initiated in the storm snow and wind-slabs, then broke into deeper layers 4 to 5 feet down. We suspect these deeper failures to be from the late January facets, possibly even the surface hoar layer that formed before the January 16 storm cycle.
Forecasters and observers throughout the Central Mountains seem to be coming to the same conclusion. Although you can trigger avalanches in the upper snowpack that can break into deeply buried weak layers, our snowpack is slowly gaining strength. It is becoming more difficult to trigger an avalanche. As the snowpack increases in depth, it is harder to find the “sweet spot,” where you are more likely to affect the deeper weak layers and trigger an avalanche. The weak layers in the upper snowpack are becoming more resistant to failure, or stubborn, at least for now. We use terms like stubborn to help describe the likelihood of an avalanche, but this season we are also using terms like catastrophic to describe the consequences of an avalanche. We have seen many very large avalanches this season run the full length of the avalanche path.