White Christmas may happen for some parts of the U.S. : NPR

This map by the Climate Prediction Center shows areas at risk of heavy snow from Christmas Day to the end of the year.

NOAA/NWS/www.cpc.ncep.noaa.gov

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NOAA/NWS/www.cpc.ncep.noaa.gov

So far, 2024 has been the warmest year on record globally and is likely to beat the record set just last year, according to NOAA. The year is also on track to be one of the warmest two years ever recorded in the contiguous U.S.

Warmer temperatures could impact future white Christmases

Historically, parts of the northern U.S., the Rockies and the Sierra Nevada Mountains have had the highest likelihood of experiencing a white Christmas, according to Kleebauer and a map by NOAA’s National Centers for Environmental Information.

The last time the majority of America woke up to a white Christmas was nearly 15 years ago, Kleebauer says. On Dec. 19, 2009, a large snowstorm blanketed parts of the Northeast starting in Virginia and dumped more than 12 inches of snow on Boston, with snow lingering through Christmas Day. Snow also fell in other parts of the country during that time, resulting in “large snow coverage across the United States, even into those areas that don’t see white Christmases too often,” he says. Texas was one of those areas.

But because of warmer temperatures driven by climate change, the coldest temperatures are becoming less frequent in parts of the country.

This map by NOAA shows the historical probability of at least 1 inch of snow on the ground on Dec. 25. The agency says actual weather conditions on Christmas Day will vary each year.

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When looking at changes in monthly and seasonal temperatures — along with the number of snowy days — “it is clear that winter is the fastest warming season across 74% of the United States, with the northeastern United States and Upper Midwest,” says Elizabeth Burakowski, a research assistant professor at the University of New Hampshire.

Since the 1970s, the U.S. has seen rapidly warming temperatures, according to the federal government’s most recent National Climate Assessment, released by the U.S. Global Change Research Program.

“As the world’s climate has shifted toward warmer conditions, the frequency and intensity of extreme cold events have declined over much of the US, while the frequency, intensity, and duration of extreme heat have increased,” the assessment says. “Across all regions of the US, people are experiencing warming temperatures and longer-lasting heatwaves. Over much of the country, nighttime temperatures and winter temperatures have warmed more rapidly than daytime and summer temperatures.”

As temperatures rise, more precipitation is expected to fall as rain instead of snow, particularly in areas in the western part of the U.S., the assessment also found. These temperatures will also lead to “earlier snowmelt, altered rates of snowmelt and evaporation directly from the snow, and longer snow-free periods,” the assessment says.

So far this winter, snowfall across parts of the U.S., including areas of the Prairie Pothole region including North and South Dakota, southern portions of Minnesota and Wisconsin, has been below normal, according to Shawn Carter, Winter Hydrology Desk lead at NOAA’s Weather Prediction Center. Government data shows that snowfall in the Sierra Nevadas and the Cascades are well above normal, while the Rockies are seeing a mix of normal to slightly below normal levels, Carter also says.

White Christmases are a sentimental favorite, but they are also a powerful example of how the world’s climate is changing.

“Seeing changes in the chances of a white Christmas is one of so many ways we may experience climate change,” Burakowski says. “When we come together as a community to address climate [change], we’re preserving so much more than snow on Christmas day.”