DC tornadoes are unusual, but don’t jump to climate change

Two tornadoes rampaged across Washington, D.C., on Thursday night, toppling fences and uprooting trees not far from the National Mall.

It’s just the latest weird weather event in a half-year full of them, though scientists say there’s no definitive evidence linking the tornadoes to climate change.

The National Weather Service (NWS) issued a tornado warning Thursday night for the National Mall, the White House, the Capitol building and Nationals Park, sending people scurrying.

One tornado came from Arlington, Va., to D.C., and the second touched down in the H St. corridor of D.C. not too far from the Capitol building, the NWS told The Hill. Both were considered relatively weak tornadoes.

Tornado warnings downtown D.C. and the National Mall, which lies near the area, are uncommon, though they happen. Previous warnings took place in 2019, 2014, 2012 and 2002, according to Connor Belak, a meteorologist for the NWS Baltimore/Washington office.

Tornado alerts are a more regular phenomenon in the broader metropolitan region, said Matthew Elliott, warning coordination meteorologist for the NWS’s Storm Prediction Center.

The larger The D.C. metropolitan region is a favorable spot for weak tornadoes because of its positioning on higher terrain, with the Appalachians and the Blue Ridge to the west and the Chesapeake Bay and the Atlantic Ocean to the east, Elliott explained.

“It’s really in a perfect position to have brief tornadoes,” he added.

Strong tornadoes, on the other hand, are much rarer and usually only hit the region every few years, while the most violent storms only happen once every decade or two, according to Elliott.

Looking at tornado trends across America, Elliott said that meteorologists are seeing an increase in the number of weaker tornadoes reported, but they don’t know whether this is due to climate change or simply due to improved weather radars and urban sprawl in previously rural areas.

But so far, Elliott said, strong tornadoes aren’t becoming more common.

“We need to continue to write this history over the next decade or so,” he continued. “These are highly localized events so determining the drivers and linkages is challenging, but these are efforts people are working on.”

To make the determination that the Thursday night events were, in fact, tornadoes, NWS teams surveyed the National Mall and Arlington areas throughout the day Friday to acquire more data, Belak, the NWS meteorologist, told The Hill. One factor they were considering was the positioning of fallen trees, which would be scattered in different directions if subject to a tornado, he explained.

Forecasters had issued the initial warning on Thursday after noticing “some signatures on the radar” indicating that some broad circulation had the potential to “tighten up,” which Belak said “is a precursor for a tornado to touch down.”

Even if scientists cannot yet link tornadoes to climate change, the D.C. storms arrived following a string of other extreme weather events over the past half-year — many of which have raised questions about the shifting climate’s connection to such conditions.

A Texas ice storm, for example, knocked out power for thousands of people in February, wildfires began scorching the West with unusual ferocity in June and Elsa just made an entrance as the first Atlantic hurricane of 2021.

One main difference, as Elliott sees it, is that forecasters can more easily determine a location’s underlying fire risk — which varies based on specific factors like elevation and the type of fuels available to feed the flames. Tornadoes, on the other hand, are much less predictable and much more acute.

“Really, you can get tornadoes anywhere,” he said.