Lightning can start fires even when there’s heavier rainfall

The crack of lightning is sure to get your attention. When it’s not part of a deluge of rainfall, it can often start a fire, depending on where it hits.

But now, a new study led by Washington State University suggests the amount of rain that can fall during a fire-starting lightning strike is triple what was thought before.

“Before, forecasters had this sort of rule-of-thumb amount that’s one-tenth of an inch of rain or less, and we found that in some situations, and in some areas, there can be up to one-third of an inch of rain that will still start a fire,” said Dmitri Kalashnikov, a PhD candidate in the WSU School of the Environment and lead author of the study published in the Journal Geophysical Research Letters.

It’s important information, formulated by the study of 4,600 naturally caused fires in the western U.S. from 2015-2021. New technology allows for higher resolution results and better data, according to Kalashnikov, who said it will help experts get a better handle on dry-lightning-sparked fires.

“It will help anticipate fires when lightning is forecasted,” Kalashnikov said. “By knowing how much rain can fall or not fall and have there be a lightning risk, forecasters and fire managers can be better prepared to deal with possible fires.”