As Christmas nears, snow at record low in U.S., elsewhere in North America

As Christmas approaches, snow cover in the United States and other parts of North America is at its lowest extent on record for the time of year – in many cases melted away by record-warm weather.

This means many locations in the Lower 48 states accustomed to a white Christmas will awaken to bare ground and temperatures more typical of early spring.

Snow cover is most depleted compared with normal near the U.S.-Canadian border, which is usually buried under a blanket of white at this time of year.

The area covered by snow has steadily shrunk over the past several days and is the smallest on record for Dec. 22 by more than five percentage points over the Lower 48 states.

Prospects of an immediate turnaround are poor. Warmer-than-normal weather is expected to prevail not only in most of North America but also in Europe and Asia, much as it has throughout 2023 – the hottest year on record for the planet.

Snow cover has declined over the Lower 48 states in large part because of unseasonably warm weather.

The Dec. 22 snow cover extent of 13.2% marks the lowest in at least two decades, according to data from the National Oceanic and Atmospheric Administration. The next lowest extent, of 18.5%, was in 2004.

The 20-year average for Dec. 22 is 35% coverage, or nearly three times the current extent.

In addition, the snow depth averaged over the Lower 48 is down to 0.8 inches. That’s 2 inches below the average for the date; the next lowest was 1.2 inches in 2004.

Snow cover is below average across almost the entirety of the northern-tier states, from Washington state to Maine.

The southern part of the Intermountain West is a rare area where snow cover is a bit above the norm, and more snow is possible there into the weekend.

Generally, snow cover numbers mark a sharp turnabout from early November, when it was around a record high for the time of year.

This year’s snow cover also marks a sharp contrast from last year at this time, when 44% of the country was blanketed in white.

Across North America, data shows snow cover values are at their lowest in at least two decades.

Several parts of southern Canada used to snow at this time of year have bare ground.

The low snow cover over North America is consistent with the situation over the entire Northern Hemisphere, which also has registered a near record-low snow extent for late December.

The deficit in snowfall over the Northern Hemisphere is a recent development after much of the past few months featured above-normal amounts. But over the past two weeks or so, values have fallen off because of warmer-than-normal weather in the midlatitudes. Europe, which was buried by snow at the beginning of December, now has a deficit.

There are areas of above-normal snow cover in northern China, Mongolia, the Koreas and northern Japan.

Heading into the final week of the year, extensive areas of above-average temperatures are forecast over much of the hemisphere.

Driven by a combination of human-caused warming and the ongoing El Niño climate pattern, episodes of chart-topping high temperatures on land and in the oceans have been frequent.

Last year at this time, the United States was dealing with a historically intense cold outbreak around Christmas. It announced its arrival with a 75-degree temperature drop in Denver, a deadly blizzard in Buffalo, New York, and record lows from Wyoming to Florida.

While conditions are expected to become more winterlike heading into January across the Lower 48, the El Niño should continue to exert a warming influence on the Northern Hemisphere overall, although its effects may slowly wane as the winter progresses.

Peak snow cover in the Northern Hemisphere tends to come around early February.

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Jason Samenow contributed to this report.