Thundersnow - Rare phenomenon may determine heavy snowfall

KANSAS CITY, Mo. -- Sometimes in the middle of a Midwestern snowstorm, thunder growls and lightning sends dull flashes among the clouds.

A University of Missouri researcher has received a $460,000 National Science Foundation grant for a five-year study to find out why.

Missouri scientist Patrick Market said for the past four years he's been looking into a phenomenon known as thundersnow, a rare event that some researchers believe foreshadows an intense snowstorm with heavy accumulation.

"There's a notion that it's rare," Market said. "One of the questions I'd like to answer precisely is how rare it is. Some of it may actually go undetected."

A thundersnow storm on Jan. 17, 1994, in Louisville, Ky., dropped about 2 feet of snow, Market said. The center of the storm, a narrow band that contained thunder and lightning, went directly over Louisville, where the biggest accumulation was recorded.

A year later, in January 1995, the same thing happened in Columbia, Mo., he said. Thundersnow was reported over the city, and that's where the harshest part of the storm hit.

A priority of the study will be to develop ways to accurately forecast a thundersnow event. Market and a team of students will make about three or four road trips each winter to chase major snowstorms in search of the elusive thundersnow.

"Thundersnow oftentimes is very small-scale phenomena which can lead to wide variations in snow amounts in very small area," said Greg Koch, a meteorologist with the National Weather Service in Pleasant Hill, Mo.

For instance, if a thundersnow event happened in the Kansas City area, he said, Blue Springs could receive 10 inches of snow while only 4 inches fell on Gladstone a few dozen miles to the north.

Market is also trying to enlist the help of anyone with Internet access who witnesses lightning in a winter snowstorm. He has set up a Web site where people can fill out a form and give as many details as they can remember.

Once his team can determine frequency of thundersnow, the next step is to look at the factors that caused it, such as updrafts similar to those found in summer storms.

Eventually, Market would like to provide weather officials enough information that they can predict thundersnow-producing storms and their outcomes with a high degree of certainty.

"I think right now we're dancing around it sometimes when forecasts are issued and you hear wording such as 'regions of particularly heavy snowfall,"' he said. "Those are regions in the minds of most forecasters with potential for thunder and lightning."