HILL AIR FORCE BASE — Northern Utah’s annual sonic boom season is now upon us.

Every year, seemingly without fail, residents along the Wasatch Front report mysterious sonic booms or unexplained tremors.

The source is usually Hill Air Force Base.

The Air Force began its yearly round of large detonation operations at the Utah Test and Training Range on Tuesday.

According to a press release from the base’s Environmental Public Affairs office, the detonations involve destroying rocket motors and solid propellant from Air Force and Navy ballistic missiles. The detonations will occur regularly now through the end of September.

In the release, Environmental Branch Chief for the 75th Civil Engineer Group Michelle Cottle said the detonations are the Air Force’s best environmental method for disposing the rocket motors and fuel.

The warhead portion of the missile isn’t detonated at the UTTR and no nuclear materials are involved in the process. Since 2012, more than 300 rocket motors have been destroyed at the UTTR, according to the base press release.

Before each large detonation, the Air Force takes atmospheric readings of wind speed, direction and other factors to determine if conditions are right for a large detonation. If the model predicts that noise is going to be louder than permitted levels at locations along the Wasatch Front, the detonation is delayed.

Cottle said the UTTR is the only facility in the United States capable of destroying the missile motors. The nation’s missile motor inventory has been disposed of at the range for more than 20 years — with crews destroying more than 1 million pounds of rocket motor propellant to date.

Though Hill tests weather conditions before the detonations, the explosions are still often heard and felt throughout the Wasatch Front.