US Chances of Snow on Christmas Have Decreased Since 1980s
2021-12-24
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1Research of 40 years of December 25 United States snow measurements shows that less of the country now has snow for Christmas than in the 1980s.
2And snow that does fall does not measure up to past depths.
3Federal weather records show that the average December temperature in the continental U.S. was a little below freezing from 1981 to 1990.
4From 2011 to 2020, it was up to an average just under 2 degrees Celsius.
5Research done by the University of Arizona for the Associated Press shows that from 1981 to 1990, on average, almost 47 percent of the country had snow on the ground Christmas Day.
6It showed that the average depth was 8.8 centimeters.
7From 2011 to 2020, Christmas snow cover was down to 38 percent, with an average depth of 6.8 centimeters.
8The change is very clear for the area that runs from Baltimore, Maryland, to Denver, Colorado, and a few hundred miles farther north to Detroit and Chicago.
9The Arizona information shows that the Christmas snow cover average went from nearly 55 percent in the 1980s to just above 41 percent now.
10Average snow depth fell from 8.8 centimeters to 6 centimeters.
11Xubin Zeng is an atmospheric scientist at the University of Arizona who ran the information.
12Zeng said the numbers are small enough that it is difficult to tell if this is a meaningful trend and, if so, if climate change or natural weather differences is the cause.
13Still, Zeng said the reduction of snow on Christmas lines up with climate change.
14Climate scientist Imke Durre said places where there is at least a ten percent chance for snow on Christmas moved north with the new normal.
15The nation's capital, Washington D.C., went from ten percent to seven percent.
16"The movement of that line is consistent with a warmer December," Durre said.
17New York, Philadelphia and Concord, New Hampshire, recorded small increases in chances of Christmas snow on the ground.
18David Robinson is a climate scientist at Rutgers University in New Jersey.
19He said the university has information based on satellite imagery that goes back to 1966.
20It shows continental U.S. snow in the last week of December has a small increase, not decease.
21"There's no trend. You just don't see it," Robinson said.
22Often people in their 60s and 70s think there are fewer Christmases with snow, he added, because the 1960s had more than the usual Christmases with snow.
23Meteorologists, or scientists who study the weather, said that temperature changes snowfall in two different ways.
24In warmer borderline areas, warmer air turns snow into rain.
25But in cooler more northern areas, where higher temperatures are still below freezing, warmer temperatures mean more snow.
26This is because warmer air holds more water which comes down as snow.
27Several meteorologists warned about finding trends in large amounts of information where both temperature and rain or snowfall are influences.
28Victor Gensini is a meteorology professor at Northern Illinois University.
29He said even with those issues, fewer Christmases with snow seem to be linked with warmer temperatures from climate change.
30I'm Gregory Stachel.
1Research of 40 years of December 25 United States snow measurements shows that less of the country now has snow for Christmas than in the 1980s. And snow that does fall does not measure up to past depths. 2Federal weather records show that the average December temperature in the continental U.S. was a little below freezing from 1981 to 1990. From 2011 to 2020, it was up to an average just under 2 degrees Celsius. 3Research done by the University of Arizona for the Associated Press shows that from 1981 to 1990, on average, almost 47 percent of the country had snow on the ground Christmas Day. It showed that the average depth was 8.8 centimeters. From 2011 to 2020, Christmas snow cover was down to 38 percent, with an average depth of 6.8 centimeters. 4The change is very clear for the area that runs from Baltimore, Maryland, to Denver, Colorado, and a few hundred miles farther north to Detroit and Chicago. The Arizona information shows that the Christmas snow cover average went from nearly 55 percent in the 1980s to just above 41 percent now. Average snow depth fell from 8.8 centimeters to 6 centimeters. 5Xubin Zeng is an atmospheric scientist at the University of Arizona who ran the information. Zeng said the numbers are small enough that it is difficult to tell if this is a meaningful trend and, if so, if climate change or natural weather differences is the cause. 6Still, Zeng said the reduction of snow on Christmas lines up with climate change. 7Climate scientist Imke Durre said places where there is at least a ten percent chance for snow on Christmas moved north with the new normal. The nation's capital, Washington D.C., went from ten percent to seven percent. 8"The movement of that line is consistent with a warmer December," Durre said. New York, Philadelphia and Concord, New Hampshire, recorded small increases in chances of Christmas snow on the ground. 9David Robinson is a climate scientist at Rutgers University in New Jersey. He said the university has information based on satellite imagery that goes back to 1966. It shows continental U.S. snow in the last week of December has a small increase, not decease. 10"There's no trend. You just don't see it," Robinson said. 11Often people in their 60s and 70s think there are fewer Christmases with snow, he added, because the 1960s had more than the usual Christmases with snow. 12Meteorologists, or scientists who study the weather, said that temperature changes snowfall in two different ways. In warmer borderline areas, warmer air turns snow into rain. But in cooler more northern areas, where higher temperatures are still below freezing, warmer temperatures mean more snow. This is because warmer air holds more water which comes down as snow. 13Several meteorologists warned about finding trends in large amounts of information where both temperature and rain or snowfall are influences. 14Victor Gensini is a meteorology professor at Northern Illinois University. He said even with those issues, fewer Christmases with snow seem to be linked with warmer temperatures from climate change. 15I'm Gregory Stachel. 16Seth Borenstein reported this story for The Associated Press. Gregory Stachel adapted it for VOA Learning English. Susan Shand was the editor. 17_________________________________________________ 18Words in This Story 19trend - n. a general direction of change: a way of behaving o proceeding that is developing and becoming more common 20consistent - adj. in agreement with something 21professor - n. a teacher especially of the highest rank at a college or university