News Photo by Julie Riddle Jeff Mercer, drone operator for the Michigan State Police, captures aerial data from the scene of the Habitat for Humanity ReStore fire on Thursday.

ALPENA — Sunday’s fire that claimed the Habitat for Humanity ReStore was likely caused by an electrical short near the store’s rear entrance, according to Capt. Andy Marceau, community risk reduction officer with the Alpena Fire Department.

Investigation by the Michigan State Police and local fire investigators with the Alpena Fire Department — including the use of a State Police drone, witness interviews, and analysis of photos posted on social media by local residents — led to the conclusion that, while the exact cause remains undetermined, the fire was most likely the result of an electrical problem, Marceau said.

No evidence suggests the fire was started intentionally, according to Marceau.

The fire, battled over 12 hours on Sunday, leveled the 100-year-old building that Habitat for Humanity Northeast Michigan has owned since 2007. Habitat is seeking a temporary location to reopen its ReStore and officials have vowed to rebuild.

DRONE INVESTIGATION

The investigation was aided by a drone buzzing above the fire remains Thursday morning, piloted by Jeff Mercer, unmanned aircraft system pilot for the State Police.

Assisted by State Police Fire Investigator Sgt. Dan Drew, Mercer managed the flight, making notations on a connected device that reflected back the image from the drone’s camera.

Use of drone technology efficiently provides high-quality photographs from above, and also creates an accurate rendering of the building.

All investigated fire scenes must be accurately diagrammed, Drew said, either by a human with a tape measure or, when available, by capturing scenes from above.

A State Police drone is programmed to fly in a pre-established grid above a scene, snapping photos at intervals and using markers placed by the drone operator around the perimeter of the scene to establish precise measurements, with the help of satellites in the sky and reception towers on land.

The drone’s photos are stitched together to create a to-scale map, which can be overlaid on an aerial photo of the building before the fire, pulled from Google Earth, establishing the exact measurements of the building’s footprint.

What would once take fire investigators many hours of work with a tape measure now can be finished in a fraction of the time, and with a greater degree of accuracy, Drew said.

Photos from above can offer evidence to help pinpoint the fire’s origin. They might show where a fire broke through the roof in relation to where investigators think the fire started, for example, adding to a fire investigator’s understanding of the event.

If a fire has not broken through the roof of a building, a drone can still be used for overhead footage, in conjunction with data taken from a laser connected to an iPad, Drew explained, which creates a detailed interior sketch of a room.

Today’s technology is a significant improvement over the days of pencil sketches using graph paper, Drew said.

In addition to fire investigations, State Police drones are used at the scenes of crashes, homicides, explosions, train derailments, and natural disasters.

Power lines over the ReStore scene, whose nearness to the fire caused firefighters to order power shut off to a majority of Alpena’s downtown during Sunday’s fire, posed a slight challenge to the drone operator Thursday, but didn’t hamper its flight.

PUBLIC CAUTION URGED

Overall, the public has been respectful of the fire scene, according to Lt. Eric Hamp, of the Alpena Police Department, with only minor slowdowns in traffic from people wanting to look at the burned building.

Positioned almost immediately across from the city’s public safety building, home base for Alpena police and fire personnel, the ReStore scene is within eyeshot of police officers around the clock.

The public is welcome to take photos from a safe distance, Hamp said, but crossing the police tape onto private property is not only trespassing, a chargeable misdemeanor offense, but also dangerous.

A pile of rubble is not a safe environment, Hamp said. Weakened by the fire and demolition by excavators, the building’s remaining walls cannot be considered safe, and cement blocks could tumble down at any moment, putting curious citizens in danger of injury.

Disturbing the fire scene also creates inaccurate data for investigators and insurance companies.

“It’s marked off with police tape for a reason,” Hamp said.

Julie Riddle can be reached at 989-358-5693, jriddle@thealpenanews.com or on Twitter @jriddleX.