Two vastly different parts of the United States each found themselves dealing with more than 20 inches of snow in the past week. A series of short waves (bundles of energy within the jet stream) rotated around a sprawling, persistent upper low in eastern North America throughout the week.

Eventually, short waves helped sharpen the trough along the East Coast, producing an intense surface low just offshore and a classic nor’easter with blizzard conditions from the Mid-Atlantic to Maine and into Atlantic Canada.

A snow band dumps mammoth amounts near the Colorado/Kansas border

While large swaths of the country received at least some snowfall during the week leading up to the East Coast blizzard, a few places got much more than a dusting.

One of the initial short waves heading into the East Coast upper low moved across the Central High Plains on Tuesday, triggering a localized but spectacular corridor of snowfall. Burlington, Colorado, received 17.0”, its second highest single-day storm in 118 years of recordkeeping behind only 19.2” on Oct. 26, 1997.

The highest point in Kansas – an optimistically named rise in the pancake-flat landscape called Mount Sunflower – happened to get the largest total reported in the storm, with 27”. Close behind were Bethune, CO, with 26”, and Kanorado, KS, with 24”.

What shocked forecasters and residents alike wasn’t that it snowed but how much it snowed. Computer models had suggested that the approaching short wave would trigger frontal development (frontogenesis) just above the surface, leading to a band of moderate to heavy snow. In line with model forecasts, a winter weather advisory was issued Monday morning for 3-5” on Tuesday, with locally higher amounts. The advisory was upgraded early Tuesday morning to a winter storm warning, and the National Weather Service (NWS) office in Goodland, Kansas, began stressing the potential for a narrow band of heavy snow.

As it turned out, the frontogenesis process was even stronger than expected, and the resulting intense snow band got locked in place for hours, as evident in the radar loop above. Roger Martin III, a forecaster at NWS/Wichita, published an illuminating deep-dive thread on Twitter with his take on what happened.

Interstate 70 and several other highways across the area were closed for hours, and a number of crashes were reported. In stark contrast to the prototypical High Plains blizzard, winds were fairly light throughout the event, and that helped limit the impact. In fact, the moisture could make this storm a net-positive event for many farmers and ranchers across the drought-stricken area.

A memorable nor’easter brings high wind and record-setting snow

By far the most intense and highest-impact winter weather of the week occurred along and near the Eastern Seaboard, from the Delmarva region late Friday night to southeast New Jersey, New York, and New England on Saturday. Blizzard warnings extended from the Eastern Shore of Virginia to southern Maine, as fierce winds accompanied the heavy snow.

Snow lovers hit the jackpot in far eastern Massachusetts, where the upper storm interacted with a coastal front that separated frigid surface air from mild, moist air offshore.

Boston’s Logan International Airport recorded 23.8” late Friday night and Saturday, which was Boston’s sixth biggest multiday storm total in records that date back to 1891. Nearly all the snow fell after midnight Friday night. Saturday’s 23.6” was a tie for the largest calendar-day snowfall in Boston history, matching the total from Feb. 17, 2003. The most recent single-day competitor was 22.1” on January 27, 2015.

Even more impressive amounts fell nearby, including storm totals of 30.9” at Stoughton, 30.4” at Sharon, and 30.0” at Quincy. Peak wind gusts included 81 mph at Yarmouth, 68 mph at Gloucester, and 45 mph at Logan Airport.

Measuring snowfall accurately in high wind is notoriously difficult. One report from a CoCoRaHS volunteer near Rockport, Massachusetts, included this summary of the conditions on Saturday: “Snowfall total highly uncertain! Blowing and drifting all day, with snow ‘falling’ horizontally. Scouring on exposed areas left some places with little to no accumulation; drifting into leeward areas built drifts of more than 3 feet. Temp this morning 11 degrees F.”

A CoCoRaHS observer in East Sandwich lamented: “Very difficult to measure snow with the blizzard conditions and the snowboard is useless! Average is best I can do.”

Eastern Long Island, New York, also got pummeled. Islip reported its second heaviest one-day total in 59 years of recordkeeping with 23.2”, behind only 23.4” on Jan. 23, 2016, and its fourth highest storm total on record (24.7”). Storm totals were much less in the New York City area, including 10.5” and 12.6” at LaGuardia and JFK airports, respectively, and 8.3” at Central Park.

Some of the other state-leading snow totals, as compiled by the NOAA/NWS Weather Prediction Center:

Connecticut:  22.0” at Norwich

Delaware:  14.2” at Lewes

Kentucky:  3.0” at Williamsburg

Maine:  19.0” near East Machias

Maryland:  14.0” at Ocean Pines

New Hampshire:  13.5” at Rye

New Jersey:  21.0” at Bayville

North Carolina: 6.0” at Beech Mountain

Pennsylvania: 9.0” at Lower Makefield Township

Rhode Island: 24.6” at Warren

Virginia:  9.5” at Oak Hill

More than 100,000 customers lost power across the Mid-Atlantic and Northeast during the hellacious storm. About a third of those remained without power on Sunday evening, mostly in Massachusetts, according to poweroutage.us.

Climate change and Northeast snowstorms: Observations clashing with models

Some types of weather are straightforward to link with climate change. The connections between climate change and both extreme heat and intensified precipitation have been confirmed in dozens of studies, some showing that particular regional heat waves would have been virtually impossible without the past century-plus of fossil fuel burning. More than 100 such studies have been published in the Bulletin of the American Meteorological Society “Explaining Extreme Events from a Climate Perspective” series, and more than 40 others have been published at the World Weather Attribution website.

Then there’s winter storms. Here, the answer to the “climate change?” question depends largely on whether you’re looking at observations, climate models, or dynamical theory. Even within these camps, the answer can vary.

While the heaviest precipitation events are clearly becoming more intense in many locations around the world – as rising temperatures allow for more moisture to fuel large-scale storm systems – it’s tougher to predict how eastern United States snowstorms will evolve over the 21st century. Especially along the Eastern Seaboard, snowfall hinges on subtle small-scale features, such as coastal fronts. Many storms intensify so much that warmer Atlantic air wraps into the storm, turning snow to rain near the coast. In theory, a cold climate might produce more snow as it warms, at least initially, but only storms that remain cold enough to produce snow could generate more of it. Other storms could push over the freezing threshold and produce heavy cold rain.

A couple of case-study modeling experiments by John Ten Hoeve show how the effects of warmer Atlantic waters on Northeast snowstorms can vary with the storm itself.

Long-range climate models insist that snowfall should become less prevalent overall across the central and eastern U.S. over the coming decades. The 2018 U.S. National Climate Assessment concluded:

As Northeast winters warm, scenarios project a combination of less early winter snowfall and earlier snowmelt, leading to a shorter snow season. The proportion of winter precipitation falling as rain has already increased and will likely continue to do so in response to a northward shift in the snow–rain transition zone projected under both lower and higher scenarios…

What’s fascinating is that the actual trend in Northeast winter storms appears to be bucking the model scenarios, at least for now. A 2020 Climate Central analysis of regional U.S. snowfall trends for 1970-2019 found snowfall decreasing nationwide in autumn, in most areas in spring, and across southern areas in winter, albeit with lots of spatial variation.

Across U.S. regions as a whole, the Northeast is the only one with snowfall increasing for two out of three seasons (winter and spring), according to the report.

Changes in snow observation techniques, especially since the 1990s, mean that at many sites there is now less chance for snow to melt or to be compacted between observations. This could lead to higher reported snow amounts from a storm today versus that same storm if it had happened 50 years ago.

Authors of a 2013 overview paper, which drew on high-quality reporting stations least likely to have such methodological biases, still concluded that the number of extreme regional U.S. snowstorms had doubled in 1961-2010 compared to 1921–1960.

And the number of high-impact Northeast storms was four times larger in 2009-2018 than in each of the five preceding decades.

In multiple papers over more than a decade with colleagues that include Jennifer Francis (Woodwell Climate Research Center) and Stephen Vavrus (University of Wisconsin–Madison), Judah Cohen (Atmospheric and Environmental Research) has argued that winter extremes in the central and eastern U.S. – including the catastrophic Texas cold blast of 2021 – are being made more likely by disproportionate warming at higher latitudes (Arctic amplification, or AA). The idea is that a chain of events related to Arctic warming may be behind disturbances of the stratospheric polar vortex in winter, allowing the vortex and its lower-altitude counterpart to drift southward and cause frigid mid-latitude incursions. This wouldn’t necessarily increase full-year snowfall, but it could lead to intense cold and snow during the intrusions.

The mismatch between observations, climate models, and theory has led to what Cohen called “divergent consensuses” in a 2020 Nature Climate Change overview featuring 32 coauthors from North America, Europe, and Asia. As noted in the paper:

Although some model experiments support the observational evidence, most modelling results show little connection between AA and severe midlatitude weather or suggest the export of excess heating from the Arctic to lower latitudes. Divergent conclusions between model and observational studies, and even intramodel studies, continue to obfuscate a clear understanding of how AA is influencing midlatitude weather.

Near the paper’s end, Cohen and colleagues hit on a point as valid in 2022 as it was two years ago:

The present lack of certainty may frustrate policymakers and the general public, but science often advances slowly on issues with great complexity and large variability. Regardless, this review of the state of research on connections between a rapidly melting Arctic and severe winter weather is timely, as large population centres in North America and Eurasia continue to experience severe cold, snowstorms and weather whiplash. Ongoing research will provide progress towards consensus on this scientifically and societally important topic.

Jeff Masters contributed to this post.

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