Unraveling the cause of San Diego’s wildfires

Like any detective working a case, the investigators looking for the cause of last week’s wildfires all over San Diego will have to sift through a combination of eyewitness accounts and physical evidence from the scenes. It could start with a downed power line or a carelessly disposed cigarette or a pile of hay that ignites on a very hot day; there are many varied ways that a wildfire can spark up. In looking for a cause, investigators must consider more than a few of them.

“We don’t rule anything out,” said bomb technician Chet Bertell of San Diego Fire-Rescue

Of nine major wildfires that erupted last week, at least one of them now has a known cause. Investigator Gordon was on the team that looked for the cause of the Bernardo Fire – the blaze that ripped through hundreds of acres between Rancho Penasquitos and Rancho Santa Fe.

“We got to an area of origin, despite look at the patterns,” stated Lawrence Gordon of the Metro Arson Strike Team.

By looking at the direction that the flames burned, as well as statements from witnesses, investigators learned that fire was ignited by a backhoe.

“We found the tracks for one of the backhoes that was out there and that kind of gave us the evidence that there was construction going on. We’ll have to look at the witness statements also.”

That’s one example of how a wildfire investigation works – often turning to some of the same tools used by police.

“Certainly, some of the same things that are at a murder scene, and a crime scene as well, is at a fire,” continued Bertell. “So, DNA is a possibility, finger prints are a possibility. If they used accelerates, we have canines that have run through some of the crime scenes as well.”

The vegetation in an area will offer all sorts of clues: trees, grass, bushes, even rocks. For example, stems of grass will bend in the direction of where a fire starts. Gordon got out a well-known reference book; it details some of the ways that certain burn patterns can help investigators.

“This has more charring on this side (of a log in a picture) than it has on the other side, and so it tells you that the fire was going (in a certain direction).”

All these investigations are guided by the scientific method.

“We look at the evidence, the physical evidence. We’re objective,” said Bertell. 

But finding the answers are not guaranteed: in some cases, evidence that points to the cause may have vanished, destroyed in the fire itself or by the work of those who are trying to put the flames out.

“We can usually get the origin, at least. But the cause of it sometimes, frankly, goes undetermined.”

A group known as the Arson Task Force is responsible for gathering information to be released to investigators. The Task Force – composed of federal, state and local agencies – is asking that anyone with information about the wildfires contact the Crime Stoppers tip line at 1-888-580-TIPS. So far, the Task Force has logged more than 40 tips.

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