Dirty snow and the growing season in North Dakota

Over at the Grand Forks Herald in North Dakota, dirty snow is apparently affecting the climate:

That could have implications for the regional climate, according to Sarah Doherty, a University of Washington scientist whose team conducted the survey.

'The (darker) snowpack absorbs more sunlight, contributing to the warming of the snowpack, warming of the surface air and earlier melt of the snowpack,' she said from her office in Seattle.

Exposing the darker soil beneath adds to that warming trend, causing more snow to melt. This self-reinforcing cycle happens each spring but, when snow melts earlier, it means there are more warmer days compared to cooler days in the year, contributing to climate change, said State Climatologist F. Adnan Akyuz at North Dakota State University.

He said farmers here enjoy a growing season that is on average 12 days longer than 100 years ago because of the warmer climate.

One of the listed causes of North Dakota's dirty snow that may lead to the warming of state: oil industry activities (i.e., drilling and other oilfield services, flaring residues, etc.).

There is an immediate problem with this oil industry blame narrative – oil production in the state didn't start to become significant and increase dramatically until 2008.  In the seven years since this time, four have had below normal temperatures.  Add to that a correlation toward cooling – not warming – in the state's annual temperatures over the last three decades, coupled with no significant trend since 1970, either, and the dirty snow hypothesis appears to run into trouble.

As for the claim that "farmers here enjoy a growing season that is on average 12 days longer than 100 years ago because of the warmer climate," this is also a problem.

The Bismarck and Williston climate sub-regions, which – according to the National Weather Service – represent about 80 to 90 percent of the state's total area, both show statistically significant declines (not increases) in the length of the growing season (i.e., first/last days less than or equal to 32º F) over the past 100 years.

Over in the far eastern portion of the state, the two small climate sub-regions around Fargo and Grand Forks do show significant increases in growing season length during the past century, but two isolated cities along the border with Minnesota do not make the state of North Dakota.

When we step back objectively and look at the state as a whole, oil industry-derived dirty snow doesn't appear to be having a significant impact on North Dakota's climate, nor is the growing season getting longer for the vast majority of the state.