Damage from past storms reveals the risks of tornado and hail activity

Don't let the slow start in this year’s severe storms fool you - larger events could be on their way

Damage from past storms reveals the risks of tornado and hail activity

Catastrophe & Flood

By Alicja Grzadkowska

Last year, the United States saw above-average activity for hurricanes, floods, wildfires and high winds. In 2018, severe convective storms in particular rained large hail down on Dallas, Texas, and Colorado Springs, Colorado, while a total of 82 tornadoes hit Western Louisiana and Arkansas, through to Southern Florida and up to Western Virginia, according to CoreLogic’s annual Natural Hazard report.

Nonetheless, the first few months of 2018 were quieter for tornado and hail activity, even though the year turned out to be a stormy one with eight of the billion-dollar disasters coming from tornadoes, hail, and straight-line winds.

“Through May, tornadoes were down 40% compared to the 10-year average. Hail was [also] down significantly, but then a lot of times, the season tends to correct itself. If you see below normal hail and tornadoes in the early spring, then a lot of years, you get an active summer that makes up for it,” said Daniel Betten (pictured), principal research scientist at CoreLogic who will be sharing insights during CoreLogic’s upcoming webinar, Investigating Tornado & Hail, on April 17. “This year, we’re again well behind in terms of what we normally see for tornado and hail activity, so we’re probably going to expect another round of [severe weather activity] in late April going into May.”

The CoreLogic report found that the total area impacted by severe hail in 2018 was actually the lowest observed since at least 2009, and was down 20% from the 2009-2017 average. That doesn’t mean pockets of the US didn’t still see significant hailstorms. The High Plains in Colorado and Wyoming, as well as portions of the Southeast, received more than double their five-year average total area of one-inch hail.

The mark that hail leaves behind can be intense. The hailstorm that hit the Dallas-Fort Worth metro area on June 06 inflicted $1 billion in damage, while a series of hailstorms on June 18 that impacted suburbs in northern Denver resulted in an estimated $276 million in damage.

When it comes to tornadoes, CoreLogic’s findings revealed that activity for the peril was down 15% from the 10-year average in 2018. Some of the notable events took place in February, when 27 confirmed tornadoes touched down in the Ohio Valley and killed three people. Another outbreak hit Mississippi, Alabama and Georgia in March, when winds up to 150mph caused extensive damage to Jacksonville State University.

Preparing for severe storms can be a difficult task, particularly when trying to protect roofs from damage.

“We know hailstorms occur every year – especially if you look at the North Texas area, they’ve had storms that cost at least $250 million every year for the last four years, including this year. For your roof, there’s not a lot you can do, except when you get a new roof. You can actually choose to put in roof tiles or shingles that are impact-resistant,” said Betten, pointing to engineering studies that have shown if higher end composite shingles are installed, hail has to be almost two inches in diameter to actually start damaging the shingles.

“There are a number of groups that are starting to advocate that when people replace the roofs after a hailstorm, they invest a little bit more money into getting these impact shingles rather than going with just the cheapest option, and, that way, it’s only the [more severe] hailstorms that actually cause damage,” he added.

While the webinar will highlight the areas impacted by hail and tornadoes, and put the first quarter of 2019 into context compared to the last three years, as well as show the impacts to homes over this timeframe, it’s important to note that the severity and frequency of these types of storms doesn’t develop in a linear way.

“There’s a lot of annual variability in tornadoes, hailstorms, and wind, so any trends you’d see over the last five years are not linear trends,” said Betten. “Some years, you’ll have big tornadoes that hit populated areas and some years you’ll have tornadoes that hit unpopulated areas. What ends up happening is we’ll have a year like 2011, [that had] one of the largest outbreaks ever and the bulk of the losses that were a result of tornadoes was really high, and then we’ll have other years in which tornadoes caused very little damage, and people tend to relax and forget about the risk.”

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