STORY AND PHOTO BY KAREN BOSSICK

Fire investigators have determined that an exploding target has caused a fire for the second straight  year in Muldoon Canyon.

But, just what are these exploding targets?

Exploding targets contain oxidizers and fuel, usually aluminum nitrate powder, that explode when struck by a high-velocity bullet. The explosion tells the shooter in a very vivid way that he’s hit his target.

Marketed under such names as Sure Shot, Sonic Boom and Tannerite, the targets generally look like jars. They are easily available at places like Sportsman’s Warehouse in Twin Falls and Bass Pro Shops.

YouTube videos show shooters blowing up junker cars and even trees with exploding targets.

While legal to purchase, they’re ILLEGAL to use them on public lands in large part because of their propensity for starting damaging fires.

The BLM fire investigator who determined the Sharps Fire was started in this manner came from Shoshone, arriving on the scene shortly after the first responders, said Dennie Smyer, a Declo school teacher who works as a fire investigator for the Twin Falls District BLM during summer.

The investigator immediately set about looking for the heel of the fire. That’s where the fire was the least active, gathering momentum as it became more active.

“Where it’s advancing we call it an angry fire.  Typically, we determine where it started advancing and walk backwards. Backing into the wind--that’s origin. We call it the area of indifference, the anchor point of the fire or the area of origin,” he said.

Investigators flag the area of origin with different colored flags, such as red flags that indicate where it’s advancing.

They also look at burn indicators on plants and rocks and other clues such as how the grass falls.

“The fire investigator in this cause probably also found fragments of the jar, indicating an explosive target,” Smyer said. “Or, he can see where the explosion took out dirt in the area down to mineral earth. It probably looks like a bomb dropped.”

It always helps to have witnesses who have seen a pickup or people in the vicinity of a fire to offer descriptions of what the people looked like or how many people there were, Smyer said.

“If people have eyes open, especially in this day of cell phones, we can find out who started it,” he added.

When three young adults started the Colorado Gulch Fire west of Hailey with fireworks a few years ago, someone steered Smyer to a hang glider who had taken a picture of those involved. Others had gotten a license plate.

When the young man denied he had started the fire, Smyer showed him the pictures he had collected and the man confessed.

“People know the damage they can do on public lands but still they do it. This year is unusual in that so far there have been more fires caused by lightning than humans. But normally that’s not the case,” he said.

“We can’t do anything about lightning. But if we can stop fires caused by ATVs and trail bikes that get  grass underneath hot mufflers, if we can stop tracer bullets and explosive targets and campfires that don’t get put out, we can keep a lot of these wildfires from happening.”