Thursday, February 27, 2020

Wither Nordic Skiing?

When it comes to the impact of global warming on snow, there will be few (if any) winners but some will suffer more than others.  Lower elevations are generally more vulnerable than higher elevation areas since temperature decreases with height.  For a given increment of warming, lower elevation regions see an event greater fraction of precipitation fall as rain, more and more substantial snow loss events, and greater loss of shoulder-season snowfall and snow compared to upper-elevation regions.

The vast majority of Nordic (i.e., cross country) ski centers and public trails are located in valleys and at relatively low elevation.  Thus, Nordic skiing is and will be suffering more than Alpine skiing, especially in ski regions where there is great vertical relief, such as Utah and the European Alps. 

For the most part, this has been a dismal Nordic ski season in Europe, including the Alps and Scandanavia.  Most of the Nordic races I've watched have featured snow only at the venue or only at the trail.  Below is an example from Falun, Sweden in early February. 

Source: NodicFocus
A big reason for this is exceptional warmth in Eurasia.  In January, for example, the biggest warm anomalies globally were in north-central Eurasia, although western Europe was also well above average.  
Source: NOAA/NCEI
Numerous warm records have fallen this winter, including the highest temperature ever measured in Scandinavia in any winter month

Extreme warmth of this type reflects both natural variability and global warming.  The dice in our warming climate are increasingly loaded to roll above average temperatures and warm extremes.  Anomalous cold can occur, such as Alaska during January, but the odds of that is decreasing and note how much of the planet is in the red in the plot above (and this is based on a 1981-2010 base period – it would be even redder if we used a 30-year base period from the early or middle 20th century).

In Utah, with the exception of Solitude, cross-country ski areas are located generally at low elevation.  For example, North Fork Park, Mountain Dell, and Soldier Hollow are below 6000 feet.  Round Valley, White Pine, and Jeremy Ranch are below 7000 feet.  We've had a good Nordic season this year, but these are elevations with vulnerable snow climates.  There will still be year-to-year variations in snow conditions, but I fear in the coming decades, we will find that the number of days of viable Nordic skiing in these areas will be on the decline, and that will be a damn shame. 

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