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Find out how much your own tornado risk is expected to increase
Jun 1, 2023
Find out how much your own tornado risk is expected to increase Houston
By   Evan Wyloge
  • City News
  • Tornado risk
  • homeowner losses
  • places to live
Abstract: This year has been a particularly bad tornado season, and not just for those living in the "tornado valley."

According to the National Oceanic and Atmospheric Administration, preliminary statistics for the start of a warming tornado season between January and March mean that 2023 will be one of the most active first quarters on record. And it could end up being one of the worst on record.

 

All of this got us wondering about the tornado risk for homeowners across the country, and the extent to which climate change is affecting the frequency, severity and location of these unstoppable storms, reminding us how small we are. So we analyzed climate risk data from real estate data provider CoreLogic to figure out how much tornado damage could cost homeowners each year, depending on where they live, and what kind of bills they could face in the future as tornadoes become more dangerous.

 

While tornadoes primarily affected the eastern part of the country, places not normally associated with tornado risk were also touched by tornadoes this year. on April 1, a 140-mile-per-hour tornado hit Delaware (measured as the widest tornado on record in the state), and on the same day tornadoes "broke out" in New Jersey, Maryland and Pennsylvania. Before that, a tornado hit Los Angeles on March 22, and a set of "twin tornadoes" hit there again on May 4.

 

For homeowners living in areas where tornadoes are likely, it's a reminder that while the chances of a tornado affecting you are slim, it can still happen. But the science on how a changing climate affects tornadoes is far from settled.

 

"There's a reason there's no agreement," said Howard Bluestein, a meteorology professor at the University of Oklahoma.

 

Bluestein said there are too many factors that can accurately predict changes in tornado frequency or intensity, from wind shear to soil moisture.


"We don't understand why some mega-storms produce tornadoes and others don't," he added.

 Find out how much your own tornado risk is expected to increase

CoreLogic's projections, which rely on widely used greenhouse gas models, show that the cost of damage from severe convective storms - the kind that cause tornadoes and other damaging winds, rain and hail - could increase by more than 10 percent by 2040 and by more than 25 percent by 2050, depending on location, and that's without adjusting for any future inflation that occurs.

 

One caveat: There is the potential for observation bias, and the number of tornadoes could increase, in part because the tools we use to observe these storms have gotten better. In addition, as more homes go up and populations grow, the damage may become more widespread. This is not necessarily because there are more tornadoes, just more homes in their way.

 

In places like Tarrant County, Texas, severe convective storms currently cause about $411 million in residential damage in any given year, according to CoreLogic. That translates into an annual risk of about $690 per homeowner. In turn, this is factored into insurance premiums.

 

But by 2040, CoreLogic expects these costs to rise by 10 percent to about $436 million countywide, or about $729 per homeowner, using the most extreme model (RCP85, which is based on growing fossil fuel use). By 2050, these costs could increase by nearly 20 percent to about $522 million, or about $872 per homeowner - and that's without accounting for the effects of inflation or population growth.

 

This is where science hits homeowners in the wallet. As risk increases, homeowners are likely to spend more on insurance premiums.

 

We plotted CoreLogic's data on a map to show which parts of the country are expected to see an increase in tornado damage costs, and by how much.

 

For the 2,610 counties with enough past tornado data to predict the future (about three-quarters of all counties), CoreLogic's data shows the estimated annual average cost to homeowners from current severe convective storms and how much that number is expected to rise under the RCP85 scenario. You can use the map below to explore this data.

 

While predicting the effects of climate change is still not an exact science, Harold Brooks, a senior research scientist at the National Oceanic and Atmospheric Administration's Severe Storms Laboratory, says improvements in home building techniques can be used to help mitigate those risks.

 

"The bottom line is we're not completely sure what climate change will cause," he said." But we know enough to know what the effects of climate change might be."

 

And that was enough to prompt him to take steps in his own home, where Brooks recently installed a tornado shelter.

 

"It's a walk-in closet with 6-inch concrete walls and a steel-reinforced door. FEMA has plans online for these," he said." The guy who poured the concrete said it was relatively simple, and when he was done, he asked if he could come over if there was a bad storm."

 

Tornado defenses aren't limited to that, though.

 

"Historically," Brooks says, "roofs were nailed down, but they were actually held in place by gravity." Most house collapses that occur in tornadoes are when the roof is lifted off. There's pressure on the walls, there's no place to go, you have upward pressure, and the roof lifts off."

 

However, builders are now using hurricane clips to prevent severe weather events that threaten the roofs of buildings. These clips secure roof rafters to the wall with inexpensive metal fittings.

 

"The buzzword in the community is 'continuous load path,'" Brooks said." These can add an order of magnitude to the pressure the roof can withstand."

 

Brooks adds that bolts that hold the walls more securely to the structure's foundation are another "relatively inexpensive thing that can reduce the risk of that damage."

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Find out how much your own tornado risk is expected to increase
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