Dry lightning can still be disastrous even when conditions aren’t so dry, a study has found. 

These cloud-to-ground strikes during little to no rainfall were previously thought to pose wildfire danger only if occurring with less than 2.5 mm of rain in a day (about 0.10 inches). A Washington State University-led study of lightning-ignited wildfires in the U.S. West found the strikes caused wildfires despite up to 7.7 mm (about 0.3 inches) of precipitation.

While still a low amount of rain, the more accurate estimation could help responders detect fires earlier, especially those known as “holdovers,” which can smolder for many days before exploding into full-blown wildfires.

“The rainfall amounts we quantified should help provide a better understanding of just how much rain can fall and still pose a fire risk,” said Dmitri Kalashnikov, a Ph.D. candidate in the WSU School of the Environment and lead author of the study published in the journal Geophysical Research Letters.

Read more at Washington State University

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