Alaska's North Slope Snow-Free Season is Lengthening

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On the North Slope of Alaska, snow is melting earlier in the spring and the snow-in date is happening later in the fall, according to a new study by CIRES and NOAA researchers. Atmospheric dynamics and sea ice conditions are behind this lengthening of the snow-free season, the scientists found, and the consequences are far reaching—including birds laying eggs sooner and iced-over rivers flowing earlier.

“The timing of snowmelt and length of the snow-free season significantly impacts weather, the permafrost, and wildlife—in short, the Arctic terrestrial system as a whole,” said Christopher Cox, a scientist with CIRES at the University of Colorado Boulder and NOAA’s Physical Sciences Division in Boulder, Colorado. The study has been accepted for publication in the Bulletin of the American Meteorological Society.

On the North Slope of Alaska, snow is melting earlier in the spring and the snow-in date is happening later in the fall, according to a new study by CIRES and NOAA researchers. Atmospheric dynamics and sea ice conditions are behind this lengthening of the snow-free season, the scientists found, and the consequences are far reaching—including birds laying eggs sooner and iced-over rivers flowing earlier.

“The timing of snowmelt and length of the snow-free season significantly impacts weather, the permafrost, and wildlife—in short, the Arctic terrestrial system as a whole,” said Christopher Cox, a scientist with CIRES at the University of Colorado Boulder and NOAA’s Physical Sciences Division in Boulder, Colorado. The study has been accepted for publication in the Bulletin of the American Meteorological Society.

Focusing on the transition seasons on the North Slope—the springtime snowmelt and the autumn onset of snowpack—the researchers found that since the mid-1970s, the spring melt has been happening earlier, and the first snow has been happening later. The end result: an increase in length of the snow-free season, by about one week per decade from 1975 to 2016. From 1975 to 2016, the spring snowmelt has arrived nearly three days earlier every decade, and from 1979-2016, snow onset has arrived later, by about 4.5 days every decade.

Read more at University of Colorado at Boulder

Image: Black guillemot eggs.  Photo Courtesy George Divoky / Friends of Cooper Island