Snow is melting faster in Kentucky as warmer average winters bring about fewer days of snow cover, according to State Climatologist Stuart Foster.
Foster, with the Kentucky Climate Center at Western Kentucky University, analyzed decades of winter weather data across the Commonwealth looking at how long snow sticks around.
In three of four cities, he found a defined downward trend in the number of days when snow covered the ground. And across the state, he's seen fewer winters where cold temperatures maintained the snow cover for weeks on end.
Kentucky hasn't experienced a severe bout of winter weather since the late 1970s. Foster's data is consistent with a warming climate.
"The thing that really stands out is not so much a year-to-year fluctuation in temperature or snowfall, but it's been more than 40 years since we've had what we would call a harsh winter," Foster said.
The state's last winter with unrelenting snow, wind and cold occurred in January 1978 when Louisville recorded more than 15.7 inches of snow, according to the National Weather Service.
Snow accumulated after several small storms in the first half of the month, only to be met with a blizzard toward January's end. Some residents were trapped in their homes while Kentucky issued a state of emergency across most of the Commonwealth.
"You used to see those types of winters with greater frequency," Foster said.
But that doesn't mean the state hasn't seen its share of cold snaps and winter weather. In 1994, Shelbyville set the record low temperature for the state at -37 degrees. In 2009, a wintry mix brought freezing rain that knocked out power for more than 600,000 homes.
Rather, Kentucky wintertime temperatures are highly variable from one year to the next, Foster said. Some winters it snows quite a bit, others not at all, he said. That's in part driven by the state's wintertime proximity to the polar jet stream – the swiftly-moving band of wind caused by the earth's rotation.
But overall, the winters are getting warmer, and as a result, the snow melts more quickly. During the last 30 years, Louisville, Lexington and Paducah have seen the average number of days with snow cover decline by about 10%, Foster said.
"With the warming conditions and the lack of any really prolonged harsh winters, we've seen a reduction of days with snow cover," Foster said.
This year's winter weather has been wet and warm with not a lot of snowfall, but a whole lot of rain, according to the National Weather Service. Far from a white Christmas, temperatures rose into the 60s on Christmas day, and hit the 70s in early January. That was followed by a third straight year of Ohio River flooding in February.
Temperatures in Kentucky have risen an average of about 1.41 degrees over the last three decades, according to the Associated Press.
The warmer climate increases the odds of extreme weather events fueling storms as well as droughts. And for the last four decades, it's meant Kentucky winters with less snow cover.