Wednesday, October 23, 2019

Welcome to the "Facet Factory"

The pattern for the next week is looking like one that will be relatively cool and mainly dry. 

Medium-range forecast models indicate that ridging will persist to our west, allowing systems to drop in over Utah from the north or northwest.  These systems will usher in cool air, but are pretty dry, with limited precipitation.

The first passes today, although you may barely notice it.  Most of the moisture remains to our east, with the Uintas and maybe the Bear River Range seeing a few flakes.  The Salt Lake Valley will remain dry and if there are flakes in the central Wasatch, they won't add up to anything. 

There's no well-defined front, but cooler air will filter in and it will lead to lower high temperatures today and a minimum near freezing at the Salt Lake City airport tomorrow morning.

The next system pushes in Saturday.  This is a stronger system thermodynamically, meaning the temperature contrast is larger and sharper.  However, it is also moisture starved by the time the airmass traverses ranges to our north and east.  Thus, mountain snow showers, which are most likely in the wake of the front Saturday night or Sunday, should be limited. 

There are, however, a few outlier members of the NAEFS, specifically from the Canadian Ensemble, that call for a bigger event.  Given that this is a tricky case of downstream development, which can sometimes throw a wrench into the system, I won't rule that out, but I think the odds are quite low. 

Thus, as one of my graduate students said yesterday, the Wasatch look to be a facet factory over the next week with generally cool or cold weather, frequent clear skies, and a thin snowpack leading to large snowpack temperature gradients and snow metamorphism into weaker, faceted crystals. 

This will be something to pay attention to in the coming days and weeks as it will likely affect avalanche conditions, including when we start to see more significant storms again. 

Apologies to my friends at the Utah Avalanche Center...


  1. Replies
    1. Well, in that case, don't call me when you need my trail breaking services.

  2. I just bought my first season pass to Snowbasin. Now I'm habitually looking at forecasts hoping we don't get a big constant blocking high pressure off to the West that redirects storms up and over Utah.

    I know it's October. But I want to ski now.