Jeff Masters Weather Blog

Sharp cold blasts punctuate one of the warmest, wettest U.S. winters on record » Yale Climate Connections

The meteorological winter of 2022-23 (December-February) was the 17th-warmest and 21st-wettest in 128 years of recordkeeping for the contiguous United States, according to the seasonal wrap-up released by NOAA March 8. The warmth was concentrated in the southeast half of the nation, while colder-than-average conditions predominated from the Rockies westward.

Heavy rains and snows along a recurrent frontal zone from California to New England led to a dank, cloudy midwinter in many areas. The moisture also went a long way toward alleviating a multiyear drought that’s been plaguing much of the country ever since an unusual three-year La Niña event (now finally waning) arrived in 2020.

The U.S. winter pattern bore several of the classic hallmarks of La Niña, which typically accentuates the normal north-to-south U.S. temperature contrasts of wintertime and fosters a strong jet stream in between. The southward extent of the Western moisture was a bit more unusual for a La Niña winter, though far from unprecedented.

Figure 1. Rankings of average temperature for each contiguous U.S. state during winter 2022-23 against 128 years of records going back to 1895. Darker orange colors indicate warmer conditions; darker blue denotes colder conditions. (Image credit: NOAA/NCEI)

A total of 29 states, all from Texas to Michigan eastward, had a top-10 warmest winter (see Figure 1 above), and it was the warmest winter on record for Massachusetts. Much of the nation has been especially mild since the first of the year: 12 states from Kentucky to Vermont had their warmest January-February period on record, and it was the warmest February on record for Virginia.

Some notable city rankings for winter 2022-23 from the Interstate 95 corridor:

  • Boston, Massachusetts:  5th-warmest
  • New York, New York (Central Park): 2nd-warmest
  • Philadelphia, Pennsylvania: 3rd-warmest
  • Baltimore, Maryland: 4th-warmest
  • Washington, D.C. (Dulles): 3rd-warmest
  • Richmond, Virginia: 2nd-warmest
  • Fayetteville, North Carolina: 4th-warmest
  • Miami, Florida: 2nd-warmest

As the effects of human-induced climate change continue to mount, the nation is warming more dramatically during winter than in any other season. Four of the 10 warmest winters on record have occurred since 2011, and only three winters this century came in colder than the 20th-century average. Since 1895, U.S. winters have warmed by roughly 2.9 degrees Fahrenheit, compared to a year-round warming of around 2.0°F and a summer-only warming of about 1.6°F.

It’s easy enough to appreciate the pleasantness of a mild winter day, but persistently warm winters can lead to all sorts of obvious and not-so-obvious problems, from a longer pollen and allergy season and a tick season that is now year-round in the Northeast to prematurely budding and blooming plants devastated by a springtime frost or freeze. (After the exceptional “warm wave” of March 2012, Michigan’s cherry and apple crops were decimated by a freeze.)

Figure 2. Models from the National Phenology Network that use recent weather conditions to estimate leaf-out and bloom-out dates indicate that most of the Southeast U.S. is seeing an early spring — in some areas, the earliest in more than 20 years. (Image credit: National Phenology Network)

The year of the quick-hitting Arctic blast

The winter of 2022-23 brought something distinct from the prolonged Arctic onslaughts that have drawn much attention in recent years, such as the February 2021 disaster centered on Texas that killed more than 260 and became the nation’s costliest winter storm on record.

Instead of a sustained deep freeze across the central and eastern U.S., this winter was marked by two quick-hitting cold blasts that set records for their speed as much as their ferocity.

  • A rampaging cold front swept from the Rockies to the East Coast in the week before Christmas, bringing some of the most intense temperature plunges in U.S. history. Among locations that saw their largest calendar-day drops in more than 150 years of recordkeeping were Denver, Colorado, from 51°F to –10°F on Dec. 21, and New York’s Central Park, from 58°F to 8°F on Dec. 23.
  • After an uncommonly mild January, another brief Arctic intrusion shook the Northeast U.S. by its shoulders on Feb. 3-4. Boston, Massachusetts, tumbled to -10°F on the morning of Feb. 4, marking the first time the city had dipped to double digits below zero Fahrenheit on any date since Jan. 15, 1957. (The city then soared right back to 51°F on Feb. 5.) Atop famously frigid Mount Washington, New Hampshire, hurricane-force winds of 96 mph gusting to 127 mph led to a wind chill late on Feb. 3 that bottomed out at an NWS-estimated –108°F, which appears to be the lowest reliably measured wind chill in U.S. annals.

The rapid-fire Arctic blast of December led to the winter’s deadliest single weather event, a highly localized blizzard in and near Buffalo, New York, starting Dec. 23 that killed at least 39 people in the area, including 31 in the city. After an unusually mild autumn, Lake Erie was unfrozen, and heat and moisture from the mild water intensified the lake-effect snow-making process that was driven by fierce westerly winds behind the sharp cold front.

A number of victims in Buffalo died on foot or in cars amid the near-zero visibility and wind gusts of up to 72 mph at the height of the fast-onset storm. The human toll was especially high within Buffalo’s Black community.

Buffalo recorded 51.9 inches across five days, contributing to the city’s third-snowiest December on record. The December 2022 storm was the city’s worst blizzard since early 1977, when a more prolonged snowstorm led to 23 deaths in western New York and paralyzed Buffalo with a mammoth multiday snowfall, including drifts of 30 to 40 feet. Ironically, instead of being goosed by an unfrozen Lake Erie, the 1978 storm was facilitated by the opposite: one of the earliest lake freeze-ups on record, which allowed vast amounts of snow to pile up on the ice and then get blown into the city.

Figure 3. Rankings of average precipitation for each contiguous U.S. state during winter 2022-23 against 128 years of records going back to 1895. Darker green colors indicate wetter conditions; darker brown denotes drier conditions. (Image credit: NOAA/NCEI)

Throughout January and February, larger-scale winter storms were shuttled along the persistently strong polar jet stream from California to New England. Wisconsin had its wettest winter on record, and seven other states from the West to Midwest experienced a top-10-wettest winter (see Figure 3).

The West’s best snow year in decades

California’s snow season got off to a promising start, with the benchmark monthly measurement at the Central Sierra’s Philips Station on Jan. 3 showing 177% of the typical amount of water trapped in snowpack (snow water equivalent) for the date. Alas, there are recent examples — such as 2013 and 2022 — where a hefty early-winter snowpack gets little reinforcement in January and February. This year, though, the winter storms kept coming, as several atmospheric rivers pumped copious amounts of Pacific moisture into the region. Even lower elevations in California got into the act with an exceptionally cold and prolonged storm in late February.

Figure 4. The snow-capped San Gabriel Mountains are visible from Sierra Madre, California (about 15 miles northeast of Los Angeles) during a break in a cold, heavy multi-day rainstorm on Saturday, Feb. 25, 2023. (Image credit: Carol Rasmussen)

Almost 12 feet (116.5 inches) of snowpack was measured at Philips Station on March 3, and the snow water equivalent of 41.5 inches was (again!) 177% of the long-term average for the date. The statewide numbers, calculated daily from 130 snow sensors deployed across California, were even more impressive: a snow water equivalent of 44.7 inches, or 190% of the norm for March 3. Just four days later, that year-to-date percentage had increased to 192% (see Figure 4).

The last time California had this much moisture locked up in snowpack in early March was 40 years ago, during an intense El Niño event in 1982-83.

Figure 4. Snow water content by region across California’s Sierra Nevada as of March 7, 2023, compared to recent years, the long-term average (1991-2020), and the record-setting year of 1982-83. (Image credit: California Department of Natural Resources)

While higher elevations were getting plastered with snow, torrential rains led to severe flooding over large parts of California during much of January. At least 22 deaths have been linked to the flooding, and damage is expected to run into the billions of dollars.

Long famous for its natural drought-to-deluge extremes, California is also highly vulnerable to the precipitation-boosting and land-parching effects of climate change. When a wet pattern sets up, as in January 2023, a warmer Pacific allows more water vapor to be funneled into California, intensifying the rains and mountain snows that such a pattern would normally bring. (See the conclusion of a recent three-part series by Jeff Masters on the increasing risk of a California megaflood.)

The onset of flooding rains around the beginning of the new year led to some of the heaviest single- and multi-day rainfalls observed in more than 150 years across central California. Here are some of the most impressive tallies for the downtown San Francisco station, which dates back to 1849, as compiled by Jan Null (Golden Gate Weather Services):

Figure 5. Weekly U.S. Drought Monitor depictions for the weeks ending on Nov. 29, 2022 (left) and Feb. 28, 2023 (right). (Image credit: National Drought Mitigation Center)

A big winter for U.S. drought relief

Widespread rain and snow took a major bite out of U.S. drought during the winter of 2022-23. Between Nov. 29 and Feb. 28, the percentage of the contiguous U.S. covered by at least some level of drought (D1 to D4, as monitored by the National Drought Mitigation Center) dropped from 57% to 38%. The extent of severe to exceptional drought (D2-D4) was nearly halved, falling from 32% to 17%.

Not surprisingly, the biggest drought relief was in the West, where wintertime rain and snow can make or break an entire water year (see Figure 5 above). The Mississippi Valley has also benefited: After drought conditions in the summer and fall of 2022 brought the river to its lowest water level on record at multiple locations, bountiful precipitation in the Mississippi River watershed during the winter of 2022-23 has brought the river to near-average water levels,

In contrast, the Great Plains — a region where precipitation is typically at its lightest during winter — saw only modest improvement. NOAA’s latest seasonal drought outlook predicts that drought will continue to grip the Plains this spring, with some expansion of drought in parts of Texas as well as in Florida.

Jeff Masters contributed to this post.

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