The January drought continues, and weather and avalanche activity has been mostly unremarkable.

Hopefully a change in the pattern this week will bring much-needed moisture to Southern Utah.

South facing slopes near La Sal Pass on Jan. 14th, 2021. 

Although a weak storm dusted the La Sals on Jan 19th, the last major loading event occurred at the end of December, producing the only observed avalanche cycle so far this season.

After this storm, the avalanche danger for the La Sals remained considerable for almost two weeks and dropped to moderate on January 11th. 

Our persistent slab problem is just that, persistent, and provides one of the trickiest forecasting challenges out of all the avalanche problems. Its helpful to remember that both the spatial distribution and the sensitivity to triggers are used to estimate the likelihood of avalanches.

This matrix above is a helpful way of thinking about avalanche danger. Sometimes the line between "Considerable" and what some folks call "Scary Moderate" is difficult to discern. 

But as days and weeks pass between loading events, slabs usually become less sensitive to triggers. 

A moderate wind event on Jan. 14th with northwesterly winds bumped up the avalanche danger above treeline temporarily.

This same storm produced 90-mph ridge top winds in Colorado. You can see the stong low pressure system centered over the midwest that lead to these winds in the video below. Additionally, the low pressure system that brought a trace of snow to the La Sals on Jan. 19th, 2021 can be seen spinning of the coast. 

https://www.ssec.wisc.edu/data/us_comp/movie

Cold overnight temperatures and shallow snow depths across the range (12"-24" depths) have lead to the continued-faceting and weakening of the entire snowpack. Below treeline on northerly aspects, the snowpack is becoming a cohesionless mass of granular facets. Although this snowpack is weak, it lacks a cohesive slab, and therefore in some places, our persistent slab goes away. Most southerly aspects at all elevations are simply devoid of snow. 

In other areas, particuallry where wind has redisttibuted snow, there are slabs that could produce avalanches. One example of this would be in north-facing, near and above treeline terrain.

As the pattern changes, expect these weak layers to wake up and be reactive to triggering.