KANSAS CITY, Mo. — As we enter the warmer seasons, storms develop because of the heat and humidity in the atmosphere and coming off the ground.
Storms can develop closer to downtown Kansas City, Missouri, where the city infrastructure causes temperatures to be warmer than outlying areas, according to a study that simulated a storm that occurred in KC in 2015.
"Two interesting findings. One is that Kansas City intensified the storm and pulled it toward the city, so that changed the storm path," explained Jiwen Fan, deputy division director of environmental science at Argonne National Laboratory.
The difference in temperature and moisture between the city and rural areas creates something like a miniature front, which then causes the storm to bend toward the city.
When the researchers simulated the storm without the city infrastructure, it took a different path that caused the storm to stay further away from the city.
“The air converges, pulls the storm toward the city, and that allows the aerosols over the city to enter into the storm to have the effect to impact the hail size," Fan said.
The study found that aerosols or air pollutants can create larger and more frequent hail. Those pollutants also give warmth to the storm and more places, called hail embryos, for the stones to grow.
“If we don’t have the organization impact to pull the storm toward the city, then the aerosol effect will not be that significant,” Fan added.
That means storms with hail, which cause 60% of storm damage nationwide, may be targeting the city more frequently.
And if the city continues to grow, that effect may become stronger.
“The impact of organization of severe storms will increase with further expansion of open area," Fan said. "But ... we are not clear if the impact will increase hail or decrease the hail.”
That decrease may have occurred March 13 as the hail sizes got smaller as the storm moved across the city, possibly because of drier air over the city.
Every storm we encounter in Kansas City is different, and the impact the urban infrastructure has on the storm could be different as well.
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