Friday, January 3, 2020

Paradoxes of Snow Measures

With the holiday's winding down, I think it is safe to say that we have been blessed with some outstanding skiing for December and the first couple of days of January.  Really, the entire month is a blur to me.  This morning, walking up the stairs to my office felt like climbing an 8000-meter peak (not that I know what that feels like), but I'm hoping to rally in time for a short skate ski later today.

Snowpack water equivalent (i.e., the amount of water in the snowpack) is above median at most SNOTEL sites.  The few sites that are below median are barely below median.  In the central Wasatch, Snowbird, Brighton, Mill D North, and Thaynes Canyon are at 138%, 119%, 122%, and 110% of median.  In the northern Wasatch, Ben Lomond Trail and Ben Lomond Peak are at 127% and 117% of median. 

Source: NRCS
Snowbird and Ben Lomond Peak have the largest snowpack water equivalents with 16 and 15.1 inches, respectively.  I did some ski touring in the Ben Lomond area a few days ago and was pleased to find a robust snowpack at all elevations.  Ben Lomond Trail, at 5972 ft, as 10 inches of snowpack water equivalent, virtually identical to the 10.1 inches at Mill D North, which sits at 8963 feet in the central Wasatch.  Some pretty robust snowpack numbers can also be found in the Oquirrhs (Rocky Basin Settlement - 12.1 inches) and Stansburys (Mining Fork 10.8 inches).  All of this indicates a great start to the ski and snow accumulation season.

Although these snowpack numbers are very healthy, you might be surprised to learn that snowfall is below average at Alta Guard.  As reported by the Utah Avalanche Center in their Jan 2 forecast, Alta Guard recorded 149" of snow in November and December, compared to an average of 162".  How can we explain this paradox?

Simply put, while the depth of new snow has been below average, the water content of that snow has been above average.  As a result, we got a lot of bang for the buck in terms of cover and I would argue ski quality. 

Many people love blower pow, but I'm not one of them.  My impression of the skiing the past few weeks is that we've had a lot of right-side up snowfalls with somewhat higher density mean water content.  In my view, that makes for great skiing.  Yesterday was the first day that I was out ski touring and the snow felt a little upside down because we had higher density snow fall on top of some lower density snow from previous days (resort skiers probably didn't notice this as much as that lower density snow was tracked thoroughly before the New Years storm).  Even then, the skiing was still good.

Please note that all of this has happened while I was in town.  Is the Steenburgh Effect is a myth borne from small sample size and confirmation bias?  Only time will tell. 

1 comment:

  1. I think it would be interesting if there were a snotel in BCC in the higher elevations or north facing aspects, Brighton is entirely open and south facing to sunlight, and Mill D North is on the lower elevation northern ridge. Snowbird snotel gets around twice as much SWE, I think that if there were a snotel just below Mount Superior, maybe high in Mineral Fork the SWE would be more similar to that of Snowbird's.