Last week, unseasonable snow covered a healthy portion higher elevations in Jackson Hole, Glacier Park in Montana and eastern Idaho, catching the attention of many.
Extreme or unusual cold weather often makes people question the validity of climate change. If it’s snowing in August, does global warming exist? For Zachary Lebo, assistant professor in Atmospheric Sciences at UW, the answer is unequivocally yes.
“We typically view the effects of global warming in terms of trends, e.g., rising sea level, rising ocean temperatures, et cetera,” Lebo said. “Just because it was cold one day in a particular location does not debunk the fact that the earth, when averaged globally and viewed over several decades, is warming.” Relating a single event like a snowstorm to global warming is difficult.
A recent study published on Nature.com, however, suggests that the reduction of ice in the Arctic is linked to an increase in the frequency of extreme winter weather events in the United States.
“But again, this is a trend,” Lebo said about the study’s finding. “As the temperature goes up, we expect to see more of these events but that does not mean that any single event is directly tied to global warming.”
Snow in August is not typical in most regions of the U.S., but snow in the high country is not unheard of.
“Given the high terrain of Wyoming, temperatures conducive to snowfall can occur at the higher elevations in any month. If ambient moisture is present, combined with the uplift created by the topography, snow can be formed,” he said.
The snow seen in Wyoming, Montana and Idaho last month may not be snow at all.
“Another interesting aspect of ‘snow’ this time of year is that it is typically not actually snow, but what we call, graupel, which is formed when liquid drops freeze in a cloud and collect tiny droplets that freeze on contact, creating opaque ice balls,” Lebo said. “This type of precipitation is more common in the transition seasons when the temperatures are closer to freezing.”
Regardless, the “snow” came and went quickly. This slightly abnormal local weather in all likelihood does not indicate something greater concerning global trends like climate change. Future August snow will likely disappear just a quickly as this year.
