Sheriff’s officials: Loud ‘booms’ in El Dorado County may come from Nevada military bases

El Dorado County sheriff’s officials say sound like explosions or shock waves reported periodically by county residents may be attributed to routine activities at military installations in Nevada.

Sheriff’s spokesman Lt. Tom Murdoch said such noises have be reported for years and have become a topic on social media. So the Sheriff’s Office recently contacted Naval Air Station Fallon and Hawthorne Army Depot in Nevada. Both installations confirmed that they conduct daily ordnance explosions for various reason.

Naval Air Station Fallon deploys aerial bombs and conducts live ordnance detonations as part of its training regimen, according to a Sheriff’s Office news release. In addition, high-speed fighter/bomber aircraft assigned to the station can break the sound barrier during flights, which often occur at altitudes higher than the elevation of the Sierra Nevada.

Hawthorne Army Depot officials reported that they conduct ordnance disposal operations from 11 a.m. to 2 p.m. Monday through Friday, hours that sheriff’s officials said are consistent with most of the explosions reportedly heard in the Swansboro area. The depot is on 147,236 acres just outside Hawthorne, and includes manufacturing, storage and demilitarization of conventional ordnance.

These explosions and operations, coupled with atmospheric conditions, geography, altitude and distances are factors in the way sound travels, sheriff’s officials said. The Naval Air Station Fallon is about 160 miles from El Dorado County’s Mosquito/Swansboro area, and the Hawthorne Army Depot is about 200 miles away, leading the Sheriff’s Office to conclude that they likely are the source of some of the noise.

Sheriff’s officials said representatives of the military installations confirmed that it was possible the sound created by the ordnance explosions and aircraft breaking the sound barrier could reach areas within El Dorado County, although they were skeptical that the detonations would be heard on a daily basis because atmospheric conditions change.

The sheriff’s records division reported that no permits for activities involving explosives have been issued within the county that could be the source of the noise.