It’s only natural: The leading cause of wildfires is lightning strikes from dry thunderstorms.
But what exactly is a dry thunderstorm?
For a storm to be called a dry thunderstorm, it must produce less than a tenth of an inch of rain.
“As we get into the summer months, we start to get a lot of drier air toward the lower levels of the atmosphere and the surface,” said Megan Syner, Emergency Coordination Meteorologist with the National Weather Service in Great Falls. “You have a lot of the moisture evaporate before it hits the ground so you can still have lightning but the precipitation can evaporate before hitting the ground.”
Montana sees a lot of these storms at this time of year.
“Other things that we see during the summer is that it can get hotter, so your surface dries faster and because of surrounding terrain it’s not uncommon for there to be not much moisture at the surface,” added Syner.
Lightning has an incredible amount of energy to fuel fires
“Lightning has way more energy and is a thousand or more times hotter than the surface of the sun,” said Syner. “So there’s a lot of energy and heat and when you concentrate that heat and energy in one particular spot and if you have fuels that are very dry on the ground, that’s the recipe for getting a fire started.”
When the rain doesn’t reach the ground, there’s nothing that can immediately put the fire out.
“In terms of the storms that create the most wildfires as a result of lightning, most of those tend to be dry thunderstorms,” Syner said.