Researchers push for more research to better understand, forecast hailstorms

·4 min read

Sep. 23—As the state and U.S. continue to invest in research and mitigation work to prevent or lessen the blow from natural disasters such as hurricanes and wildfires, researchers also are urging people to pay attention to a weather phenomenon that might not seem as dangerous but has cost Colorado and the country billions in home and vehicle damage while still imposing harm to people and animals.

This weather phenomenon is a hailstorm, and although it can sometimes produce tiny ice balls smaller than peas, it has been known to create much larger, more destructive hailstones.

"In the Front Range, there is very damaging hail at times," said Andrew Heymsfield, a senior scientist with the National Center for Atmospheric Research. "In 2017, there was a $2.3 billion damaging hailstorm that hit Denver. Then the next year, there was one in Colorado Springs that killed animals at the zoo."

Heymsfield and other hail experts met on Thursday at NCAR in Boulder to speak during a news conference for the Second North American Workshop on Hail & Hailstorms about the damage and danger hailstorms pose and the way forecasting can be improved to help mitigate future destruction.

In the 1970s, the U.S. conducted the National Hail Research Experiment to test a Soviet Union seeding hypothesis that said hail could be mitigated by cloud seeding, which is a weather modification technique aimed to improve a cloud's ability to produce rain or snow by introducing tiny ice nuclei into certain types of subfreezing clouds. But the hypothesis failed.

"Since then, (mitigating hail) didn't seem to be a major hazard," Heymsfield said. "Maybe if Washington, D.C., had been hit by hail it would have been different, but a major part of it is also that the major population centers — the east and west coasts — were not getting hit by hailstorms as (hazardous as what) happens in the high plains and the Midwest. Now this perspective is changing."

Now, he and other researchers are looking to improve hailstorm research and have proposed a new field project they are calling the In-situ Collaborative Experiment for Collection of Hail in the Plains, which they proposed to the National Science Foundation.

"It would be in essence, us chasing hailstorms," said Rebecca Adams-Selin, with Verisk Atmospheric and Environmental Research. "Our goal would be to sample the storms and with mobile radar data (to) be able to watch them (and) fully understand what's going on, and then also get out ahead of the storm and put down all sorts of instrumentation, let it go past and then hail will fall on all of our instrumentation."

From there, scientists could learn about the size distribution of hail, how far hail falls across a storm and how it varies, Adams-Selin said.

"There's hundreds of different questions — what kind of shapes (of hail) will fall? How can we try to identify that using our radar datas?" she asked. "There's a lot of exciting things that can come out of this, and there's obviously been a lot of technological advancements in the last 40 years. This could make a big leap forward for hail science."

Not only are researchers wanting to improve research on hailstorms and forecasting methods, they are also pushing for alternative building methods to construct homes that are resilient to hailstorms, especially as more development occurs in hail-prone regions, said Ian Giammanco, senior director for standards and data analytics and lead research meteorologist at the Insurance Institute for Business & Home Safety.

"Hail is about 60% to 80% of that damage caused by severe thunderstorms every single year," Giammanco said. "A lot of us gravitate to tornadoes or the wind damage that we see so frequently, but hailstorms happen all of the time and it hits a lot of stuff and that's a lot of material that has to get replaced."

As more and more homes are built, they are not all being built with materials that can weather hailstorms, Giammanco said. In the past year, hail has been reported 28 times in Boulder County. Specific data was not available to show how much damage Boulder County experienced from hailstorms, but Colorado's most costly catastrophe was from hail. It occurred in the Denver-metro area in 2017 and caused $2.3 billion worth of insured losses, according to data from The Rocky Mountain Insurance Association.

Heymsfield said that last year, the Front Range did not experience an extensive amount of damage but from 2017 through 2019, Boulder County had very hail-active areas that resulted in a lot of damage.

"That's the whole goal there — how do we bend down this loss curve?" Giammanco asked. "How do we take all of this science information we have been talking about and apply it to at least start whittling away at the damage we've seen year after year from hail events?"