Trailside Talk: Weather extremes

A land of high mountains and low valleys, Great Smoky Mountains National Park is a place of extremes.

This is shown prominently in the wide sweep of weather across the park, as measured by numerous weather stations, including five owned by the National Weather Service and operated by park employees. 

The highest is located at Mount Le Conte, the third tallest peak in the park. The lowest is at park headquarters near the Gatlinburg entrance. As might be predicted, the differences in weather at the two locations are striking. For example, the wettest year on record at park headquarters was in 2018 with 73.71 inches of precipitation. The same year atop Mount Le Conte saw 111.43 inches.

Weather stations both high and low help to track the frightful occasions when the skies decide to open over the Smokies and unleash their fury all at once. On October 15, 2014, the Le Conte station reported the largest recorded downpour in Smokies history with 5.56 inches of rain in a single day. The largest snowfall in the park came to an end March 13, 1993, in what came to be known as the “blizzard of the century.” Sixty inches of snow fell atop Le Conte, trapping LeConte Lodge visitors for days. During the same period, 30 inches fell at park headquarters. At Newfound Gap, parked cars were buried in 14-foot snowdrifts.

Because of its elevation, Le Conte has recorded zany weather numbers over the years. The mountain has had temperatures below freezing every month of the year (yes, even July). The earliest freeze—30 degrees Fahrenheit—was recorded there on July 21, 2009.

The first freeze and last freeze of each season provide evidence of how a changing climate is warming the park, said GSMNP air resource specialist Jim Renfro.

“The difference between the first freeze and the last freeze is basically your growing season,” Renfro said. “And it’s lengthening. The first freeze in the fall is coming later and later, and the last in spring is earlier and earlier, meaning it’s warming up. At Le Conte, it’s lengthening about a day a year. Over a 30-year period, the growing season has lengthened about 30 days, which means winter here is shrinking. We’re projected to be warmer and wetter. That’s our long-term trend. When you look back over the last hundred years, it’s warmer and wetter.”

For many years, park rangers made daily stops at the Newfound Gap weather station to record numbers. This became a challenge during rough winter weather, so the park installed a sensor that can measure the distance from its location to the ground. 

“If the distance shortens, it records that,” Renfro said. “So, it can tell, for example, that the snow depth is four inches. We’ve gone up there many times to measure it, and it’s really accurate. We turn it off in the summer because it’s just measuring grass height then—but it could let us know to get the weed-eater up there.”

The park’s weather measurements across the years provide excellent baseline information for scientists and others who come to the Smokies for research projects. For visitors, the knowledge of what to expect at the peak of summer and the coldest stretches of winter can also be beneficial. 

Mike Hembree is a veteran journalist and the author of 14 books. He has visited 26 national parks and hopes to add many more to that list.