Lightning-initiated wildfires tear through Southern Utah: Here’s how one strike can start a blaze

PINE VALLEY, Utah (ABC4) — Amid intense wildfire dangers in Southern Utah, lightning continues to pose a risk for more fire starts. The science behind how lightning can spark a fire is more complex than it might seem.

85% of wildfires are caused by humans, U.S. Forest Service data shows. However, lightning is known as a common natural igniter of wildland fires, as is the case in the Forsyth Fire.

The Great Basin Complex Incident Management Team 7 (CIMT) confirmed the Forsyth Fire, which has destroyed 13 structures and over 8,200 acres of land in Pine Valley, Utah. Crews say the fire is still 0% contained.

A study by NASA, which examined 26 years of lightning-initiated wildfires, showed that nearly one-third of wildfire events are caused by holdovers, meaning at least a day passed between initial lightning strike and fire reports.

A staggering 57% of lightning-initiated fires were found to be caused by single stroke flashes, the report found.

“Results highlighted the need for reassessing the role of positive [cloud-to-ground] lightning and subsequently long-lasting current in wildfire ignition started by lightning,” NASA added.

According to the National Park Service, lightning has two components: leaders and strokes. Leaders are a type of “probing feeler” sent from the clouds of an electrical storm. Then come streaks of light that are a series of strokes, producing the lightning bolt itself.

NPS also details two different types of lightning: cold and hot. Cold lightning acts as the return stroke of a lightning bolt, producing a quick, intense electrical current. Hot lightning contains less electricity but lasts much longer. Most naturally sparked wildfires are caused by hot lightning.

As multiple lightning-caused fires tear through Southern Utah, the Bureau of Land Management is raising awareness of the dangers firefighters face while fighting wildfires.

“These storms can cause erratic weather conditions that lead to extreme fire behavior,” BLM said in a social media post.

BLM says firefighters who see a thunderstorm approaching should move to a safe, open area with smaller trees, drop their tools, and sit on a fire pack. Officials also direct firefighters to avoid working on the fire line until 30 minutes after the storm has passed.