Snowfall down, temps up during holidays
KNOXVILLE (AP) — It may be looking a lot like Christmas in the shopping malls, but a warming trend over the past half-century points to fewer real snowflakes from Thanksgiving to Christmas Eve.
An Oak Ridge National Laboratory analysis of weather data from 1948 to 2001 for the 30-day holiday season found that for most of the country temperatures are rising and the amount of snow is falling.
Of 260 weather stations reporting to the National Oceanic and Atmospheric Administration, 197 show a decline in snowfall during the Nov. 25 to Dec. 24 period, said meteorologist Dale Kaiser, who conducted the study.
The decrease is especially pronounced east of the Mississippi River, where 117 of 125 stations had an average of five fewer snow days, from the Midwest to the Northeast, he said.
Some examples: Batavia, N.Y., had 12.5 fewer snow days during the holidays; Medford, Wis., 11.7; Towand, Pa., 10.3; and Sault Ste. Marie, Mich., 9.3.
Declines among major cities: Columbus, Ohio, 7.8 days; Indianapolis, Ind., 6.5; Minneapolis, Minn., 6.0; Philadelphia, 5.2; Chicago, 4.8; Washington, D.C., 4.3, and Nashville, Tenn., 4.1.
“We can conclude that over roughly the last half of the 20th century that snowfall over most of the country is becoming less common,” Kaiser said.
The Central Rocky Mountain states extending eastward into the Central Plains of Nebraska bucked the trend, with a few stations in Utah and Colorado seeing nearly 10 more days with snowfall.
Provo, Utah, had 9.8 more snow days; Plevna, Mont., had 8.6 more; Dillon, Colo., had 8.3 more. So did Sioux Falls, S.D., with 3.7 more snow days and Boulder, Colo., with 3.5 more days.
Kaiser generally found temperatures following the snowfall trend, with stations in the East showing an overall warming trend of 2.7 degrees, and the Central Rockies slightly cooler.
While identifying the trends, Kaiser refused to reach broader conclusions about what’s behind them.
“Although this work shows real changes over parts of the U.S. in snowfall days and temperature for this 30-day period, this cannot be used to draw conclusions about changes in weather over the entire winter, nor do these findings necessarily relate to the broader issue of global warming,” he said.
Kaiser noted that some reporting stations in Tennessee, where winter temperatures can vary widely from year to year, pre-Christmas snowfalls were common in the 1940s and 1950s, but have been rare in the past decade. That was the case with Clarksville as well as Murfressboro-Nashville.
Kaiser said he couldn’t come up with a major trend for Oak Ridge, about 15 miles west of Knoxville. The city usually gets about one snow day of pre-Christmas snow a season but has received as much 12 days in 1963 and 11 days in 1994.
No trend for Covington-Memphis could be developed simply because it doesn’t get enough snow to count, he said.
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