Is it just me or does it feel like we’re having more tornadoes in and around New Hampshire these days?
I wouldn’t be surprised if we were. The climate emergency is making everything else worse so it’s only logical that it would increase the number of dangerous wind funnels descending from the heavens.
But not so, says the state climatologist, although it’s hard to say what might happen in the future.
Two tornadoes have been confirmed in the state this year, one in Charlestown and one in Chesterfield. (Maybe Chichester should be worried.)
But that’s not an unusual number, said Mary Stampone, an associate professor at UNH who is the state climatologist. Since records began in 1951 there have been 111 tornadoes registered in the state, or a little under two a year.
“They’re usually minor,” added Stampone, a self-described tornado geek.
This year’s tornadoes both registered as EF-1 on the five-point Enhanced Fujita Scale, named after one of the men who established it. Their winds were less than 110 mph and the funnels didn’t last long or travel far. Trees were torn down and some buildings damaged but nobody was hurt.
So far as I can tell there has only been one major tornado recorded in the state, an EF-3 (136 to 165 mph winds) in Exeter in 1953, and only one fatality during that period. It occurred when a house collapsed in a 2008 tornado that traveled 50 miles through the middle of the state, perhaps the most destructive such storm we’ve seen.
So why do I think there are more tornadoes now?
Partly because dash cams and cell phones mean I can see them. That Charlestown storm in particular was captured on some startling video; Stampone uses one in her class to help students learn to judge what is and isn’t a vortex. “It’s an exercise to mimic field surveys,” she said.
Another factor: Better radar.
Eric Fisher, chief meteorologist at Boston’sWBZ-TV, posted a chart on Twitter showing that the number of tornado warnings issued by that city’s National Weather Service forecast office has jumped sharply in the past decade, from fewer than 10 a year to more than 15. Fisher noted that in 2011 the radar “was upgraded to dual-pol. Makes it easier to see rotation in storms.” (I don’t know what dual-pol is, either, but I assume it’s good.)
Here is a key point: a tornado isn’t a tornado until it reaches the ground. Confirmation requires a National Weather Service team going to the site to ensure it wasn’t just a very strong windstorm or microburst.
Tornado warnings indicate that the right mix of warm and cool air and moisture are creating spinning vortexes that have the potential to become tornadoes, but it doesn’t mean they actually become tornadoes. Maybe hearing about all these warnings online could be making it seem to me like more actual tornadoes are happening.
Which leads to a question: Are there more tornado warnings because climate change is making it easier for tornadoes to form? Warmer air has more energy in it and creates more evaporation, leading to more moisture in the air, so the potential is there.
But Stampone says that’s not enough. “For tornadoes you’re going to have lift and you need to have the spin” and it’s not clear whether climate change is affecting those two factors. Climate modeling isn’t exact enough to forecast how the changing climate will alter tornado patterns in New Hampshire, she said.
One thing with tornadoes does seem to have changed: The location of Tornado Alley. This stretch of the Midwest centered on Kansas is infamous for its tornadoes – it is “Wizard of Oz” territory – but in recent years more tornadoes have been seen further east, in Missouri and Tennessee.
“Is that a function of having better observations, or a function of changing Jet Stream-level dynamic .. making it happen further east now? We don’t know,” said Stampone.
Still, if Tornado Alley can change maybe our tornado pattern can change, too. Maybe more tornadoes will come our way. Or fewer. Or something else – like a plague of frogs.
The way things are going, that wouldn’t surprise me.