It’s common knowledge that heat waves can create dangerously dry conditions. We’ve all seen hazard signs warning of the spread of camp- or wildfires and many of us have experienced the devastating effects of “fire season” first-hand. However, few people expect a fire to break out in their own yard, even during record-breaking heat.

Unfortunately, this was the case last week for the Wise family in El Dorado Hills, CA when their backyard mulch spontaneously combusted. Here is exactly what happened in the Wise family’s backyard, as well as information on why the mulch combusted and how to prevent mulch fires in your own yard.

How the Mulch Caught on Fire

Surveillance video footage shared with CBS News Sacramento shows the fire suddenly breaking out in the Wise’s backyard. The flames grow rapidly to torch the ground and surrounding trees, waking Mike Wise up in the middle of the night.

He describes his immediate reaction: “I was kind of stunned at first. I couldn’t imagine why my yard would be on fire.” He continues, “This is new to me. I’ve never heard of bark literally catching itself on fire.”

Fortunately, Wise was able to extinguish the fire using his garden hose. Afterward, the mulch was charred and, in the words of 7-year-old Grant Wise, “the board that lines [the mulch] from the grass and the little sprinkler have almost melted completely.”

Why Mulch Can Catch on Fire

According to Homes and Gardens, mulch can spontaneously catch fire when it is laid too thickly. In the video, the reporter explains that he Mike had just had the mulch put in just that day. Presumably, it was extra dry from the new installation and had yet to be watered. Additionally, as Grant Wise mentions, the record-breaking heat played a major role in igniting the mulch. “Well, it was like 108 yesterday, so that could’ve probably cooked the bark pretty good.”

How to Prevent Mulch Fires

The first step to preventing mulch fires is laying the mulch in an appropriate thickness: 2 to 3 inches. From there, avoid any substantial piles of mulch, especially around other flammable plants like dry trees. Keep the mulch irrigated as you would a lawn and surround it with fire-resistant materials. In Weiss’s case, the properly watered grass helped stop the spread of the fire, but you could also use a gravel yard cover.

How to Stay Safe in Fire Conditions

It’s important to create fire safety plans before you need them. Read up on how to prevent home fires as well as which household items can spontaneously combust. Finally, keep wildfire preparation products on hand and, whenever possible, avoid working outside in poor air quality. Stay safe out there!

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