8 Climatic Facts About Our Abnormally Warm Winter

Christof Stache/AFP/Getty Images
Christof Stache/AFP/Getty Images

It was warm this winter. Freakishly warm, in fact. It was warm enough that we probably should have felt guilty for enjoying it so much. After all, any time you can open your windows when you’re supposed to be shivering and watching travel shows for warmth is a strange situation. Most of the United States just lived through one of the warmest Februarys on record to close out one of the warmest winters on record. Here are some statistics that will show you just how unusually balmy it’s been for the past three months.

1. THIS FEBRUARY WAS WARMER THAN NORMAL.


A map of how warm this February was compared to previous years. Stations showing a ‘1’ experienced the warmest February ever recorded at that location. Image Credit: SERCC

 
It shouldn’t come as any shock that February’s temperatures were above-average when you crunch the numbers. Out of 888 weather observing stations across the lower 48, a solid 60 percent of those stations (or 534 locations) saw their top-10 warmest February on record this year. Even worse is that 186 of those locations—scattered from the depths of Texas to the Canadian border—recorded their all-time warmest February, with some records stretching back more than 100 years.

2. THE WHOLE WINTER WAS WARMER THAN NORMAL.

Not only was this past February a record-breaker, but the whole winter was warm on average. Data from the Southeast Regional Climate Center shows that over half of those 888 weather observing stations in the contiguous United States saw this winter place among the top ten warmest winters ever recorded, with almost all of the toasty stations residing east of the Rocky Mountains. Most of the all-time warmest winter records were set in the southern part of the country, including cities like Houston, Texas, and Raleigh, North Carolina.

3. THE WARMTH KEPT MOST OF THE SNOW AT BAY.


Taken just one day apart in early February, two views of the downtown Manhattan skyline—one warm and sunny, the other obscured by snow—as seen from the Brooklyn Heights Promenade. Image Credit: Spencer Platt/Getty Images

 
As you can imagine, you’re not going to find very much snow when it’s relatively toasty out there. There have been other winters with less snow than most places saw this year, but the differences are negligible. Take Washington D.C., for example. Washington National Airport, which sits just across the Potomac River from the capital city itself, typically sees about 15 inches of snow every year. They’ve recorded just over an inch of snow this year. On the list of least-snowy winters in the nation’s capital, this winter ranks fourth since records began in 1940.

4. CHICAGO SAW NO SNOW IN JANUARY OR FEBRUARY.

Even more unusual is the fact that Chicago went through the entire months of January and February without seeing one lick of snow cover the ground. According to the city’s National Weather Service office, this was the first time in the city’s 146 years of recording weather observations that they didn’t see any snow on the ground during the dead of winter. The city saw a foot-and-a-half of snow spread out over several storms during the month of December, but all of that snow melted by Christmas. The most they’ve seen since then is a “trace” of snow, which is snow that falls but instantly melts when it hits the ground.

5. THE GREAT LAKES WERE RELATIVELY ICE-FREE.

While we’re looking toward the Midwest, it’s worth noting that the Great Lakes were surprisingly ice-free this season. The five lakes only saw about 15 percent of their surface covered by ice during the season’s maximum extent on February 8, and what little ice did form this year is rapidly melting as warm air continues to bathe the enormous bodies of water. Since NOAA began keeping records back in 1973, a typical winter sees a little more than half of the Great Lakes covered with ice during the peak of winter, but the coverage has been as low as 11 percent, a record achieved in 2002.

6. THE LEAVES LOVED IT, THOUGH.


A map showing how unusually early (or late) leaves first showed up on trees in 2017 compared to normal. Image Credit: USANPN

Humans aren’t the only organisms enjoying the reprieve from winter’s grip. The USA National Phenology Network tracks the extent of trees budding and growing leaves as spring begins to set in. According to their observations, almost every part of the United States that has leaves on its trees right now saw those leaves appear a full three weeks ahead of schedule—what it calls "very large anomalies." This is welcome news for the birds and the bees, but if there’s a sudden cold snap in March—which isn’t unheard of—it could do some serious damage to any plants that are suddenly more vulnerable than normal.

7. THE WARMTH LED TO SOME SEVERE THUNDERSTORMS.

When you put an active weather pattern together with warm and unstable air, it’s almost inevitable that you’ll wind up with strong thunderstorms at some point. We saw several rounds of severe weather this spring, resulting in at least three fatalities on the last day of February. Severe weather is fairly common in the southeast due to its proximity to muggy air over the Gulf of Mexico, but severe weather stretched unusually far north this year. A tornado that touched down in western Massachusetts on February 25 was the only tornado ever recorded in the state during the month of February, and quite possibly the farthest north we’ve ever seen a tornado since reliable records began in 1950.

8. SO WHY HAS IT BEEN SO WARM?

Why has it been so warm in the east and so cool and active out west? It has to do with the jet stream. For the past couple of years, there’s been a huge ridge in the jet stream over the West Coast that kept them warm and dangerously dry, while the jet stream dipped south and brought cooler, more active weather to the rest of the United States. That pattern broke this year, essentially reversing itself and keeping the warmth-inducing ridge out east while the jet stream in the west keeps dipping south and bringing them a steady stream of rough weather. One theory as to why the pattern flipped is the disappearance of the infamous “Blob,” a nickname given to an unusually warm area of water in the northeastern Pacific Ocean. That water cooled off, which may have allowed the jet stream to readjust itself into the pattern we’ve seen this winter.

Storm Leaves Homes Along Lake Erie Covered in Up To Three Feet of Ice

Houses along Lake Erie's shoreline were pummeled with sheets of icy water during a storm last week.
Houses along Lake Erie's shoreline were pummeled with sheets of icy water during a storm last week.
John Normile/Getty Images

This past weekend, lakeside residents of Hamburg, New York, awoke to find their neighborhood transformed into a full-scale replica of Frozen’s ice-covered kingdom, Arendelle.

According to CNN, gale force winds produced giant waves that sprayed the houses along Lake Erie with sheets of water for two days straight, covering them in layers of ice up to three feet thick.

“It looks fake, it looks surreal,” Hamburg resident Ed Mis told CNN. “It’s dark on the inside of my house. It can be a little eerie, a little frightening.”

While the homeowners are anxious for the ice to melt, they’re also concerned about what could happen when it does.

“We’re worried about the integrity, of structure failure when it starts to melt, because of the weight on the roof,” Mis said.

He added that this is the worst ice coating he’s seen since he moved to the area eight years ago—but it’s not because they’ve had a particularly harsh winter. In fact, just the opposite is true. According to The Detroit News, warm winter temperatures have caused ice cover on the Great Lakes to drop from 67 percent in 2019 to less than 20 percent this year.

“Lake Erie typically has significant ice cover by this time of the year, and that protects the shoreline from these battering storms,” The Weather Channel’s winter weather expert Tom Niziol explained in a video.

The phenomenon has created another unforeseen issue for Hamburg’s coast, too: Tourism. The local police department posted a message on Facebook on Sunday, March 1, asking people to keep off both the “extremely unsafe and unstable” ice and people's private property.

[h/t CNN]

What is Lake-Effect Snow?

Tainar/iStock via Getty Images
Tainar/iStock via Getty Images

As you probably guessed, you need a lake to experience lake-effect snow. The primary factor in creating lake-effect snow is a temperature difference between the lake and the air above it. Because water has a high specific heat, it warms and cools much more slowly than the air around it. All summer, the sun heats the lake, which stays warm deep into autumn. When air temperatures dip, we get the necessary temperature difference for lake-effect snow.

As the cool air passes over the lake, moisture from the water evaporates and the air directly above the surface heats up. This warm, wet air rises and condenses, quickly forming heavy clouds. The rate of change in temperature as you move up through the air is known as the "lapse rate"; the greater the lapse rate, the more unstable a system is—and the more prone it is to create weather events.

Encountering the shore only exacerbates the situation. Increased friction causes the wind to slow down and clouds to "pile up" while hills and variable topography push air up even more dramatically, causing more cooling and more condensation.

The other major factors that determine the particulars of a lake-effect snowstorm are the orientation of the wind and the specific lake. Winds blowing along the length of a lake create greater "fetch," the area of water over which the wind blows, and thus more extreme storms like the one currently pummeling the Buffalo area. The constraints of the lake itself create stark boundaries between heavy snow and just a few flurries and literal walls of snow that advance onto the shore. The southern and eastern shores of the Great Lakes are considered "snow belts" because, with winds prevailing from the northwest, these areas tend to get hit the hardest.

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