Loud "booms" heard on West Slope caused by planes on maneuvers

Several residents on the west slope of El Dorado County have periodically made calls into law enforcement about "loud booms" heard over many days so the Sheriff's Department investigated several possible sources.

It turns out that the sounds were created by Naval Air Station Fallon and Hawthorne Army Depot maneuvers over the County, mostly heard in the area of Swansboro. The daily ordinance explosions and high speed fighters and bombers breaking the sound barrier have been determined to be the cause of the noises.

Naval Air Station Fallon deploys aerial bombs and live ordinance detonations as part of their training regimen. Flight paths of bombers and fighter planes are often higher in altitude than the elevation of the Sierra Nevada that separate the County from the two bases.

They said they conduct these kinds of operations at various hours throughout the week. Hawthorne Army Depot said it conducts ordinance disposal operations Monday through Friday between the hours of 11:00 a.m. and 2:00 p.m. These particular hours of operation are consistent with most of the explosions reportedly heard in the Swansboro area of the county. The Depot is housed on about 147,236 acres just outside of Hawthorne Nevada with manufacturing, storage, and demilitarization of conventional (non-nuclear) ordinance capabilities.

All of these explosions and operations coupled with atmospheric conditions, geography, altitude, and distances all play a factor in the way sound travels.

Considering that the Naval Air Station in Fallon Nevada is about 160 miles away from the Mosquito / Swansboro area, while the Hawthorne Army Depot is located approximately 200 miles away, they are most likely the source of some noise. Military personnel from both locations confirmed it is possible for the sound created by these explosions and breaking the sound barrier at altitude can reach areas within El Dorado County. However, they remain somewhat skeptical that these detonations could be heard from this distance on a daily basis as atmospheric conditions change.

According to the Sheriff’s Office Records Division, no local explosive permits have been issued that could also be the source or cause of the noises.