(Idaho, USA) Blaine County sheriff's deputies responded to reports of loud booming noises in western Hailey last week, but could not find the source of the sounds.

Speculations about the source of the sounds, which were heard across the city and to the west, range from supersonic aircraft to explosive targets.

Sheriff's Lt. Jay Davis said that following reports of the sounds, deputies drove on Friday, March 2, into Croy Canyon and heard them also, but could not find their source.

"We have some suspicions," Davis said, including explosive targets, but he said the investigation is ongoing.

Tannerite is the trademark name for an ammonium nitrate/aluminum powder-based binary explosive used in target practice.

A gunshop owner in the Wood River Valley who asked to remain anonymous said that Tannarite, if used in sufficient quantities, could produce loud enough explosions to be heard far away. He said a high-caliber rifle had to be shot into the material to detonate it.

Dan Freeman, who farmed in Croy Canyon a few years ago, said he heard "ground-shaking" explosions from far to the west-southwest many times. He said his wife heard the explosions Friday from their home on Buttercup Road west of Hailey.

"In Croy Canyon, we sometimes would hear five to 10 explosions in a day, some bigger and some smaller," Freeman said. "I think we were hearing explosions from the bombing range east of Mountain Home Air Force Base."

Air Force Base Master Sgt. Andrew Leonard said he reviewed flight logs for supersonic aircraft at Mountain Home for last Friday and determined that multiple F-15E jets had flown in "military trains" about 50 miles west of Hailey at the time of the reports. However, Leonard said the jets are not allowed to fly fast enough in that area to break the sound barrier, which sets off sonic booms that can be heard many miles away.

Leonard said a bombing range west of Mountain Home could not be the source of loud noises more than 50 miles away in Hailey.

"We can barely hear them from here," he said.

Tony Evans: tevans@mtexpress.com