Since the late 1970’s, the winter storm track located above the western US has slowly been sliding north. The combination of global warming and the ozone hole have forced this change, making for fewer winter storms in the American Southwest.
And according to new research from the University of Arizona in Tucson, the hotter and drier springs being inflicted upon Southern California, Arizona, Nevada, Utah, western Colorado and western New Mexico, are a direct result of the poleward shifting storm track.
“We used to have this season from October to April where we had a chance for a storm,” said Stephanie A. McAfee, a doctoral candidate in the UA’s department of geosciences. “Now it’s from October to March.”
“When you pull the storm track north, it takes the storms with it,” said McAfee. “During the period it’s raining less, it also tends to be warmer than it used to be. We’re starting to see the impacts of climate change in the late winter and early spring, particularly in the Southwest. It’s a season-specific kind of drought.”
Some of the consequences that are brought about by seeing warmer conditions earlier in the year include affects that take place on the snowpack, said McAfee. With less snow and rain falling due to a shorter winter, there is less snowmelt and runoff into lakes and rivers.
The future does not bode well either, when looking at computer models, which suggest that the storm track will continue to slide northward, further decreasing rainfall in the southwest of continental America.
“We’re used to thinking about climate change as happening sometime in the future to someone else,” said McAfee’s co-author Joellen L. Russell, “but this is right here and affects us now. The future is here.”
Image Credit: Stephanie McAfee, the University of Arizona, 2008.