Possible Loud ‘Boom’ in San Diego Wednesday – NBC 7 San Diego

Loud booms may be heard in parts of San Diego Wednesday but it’s no cause for alarm — it’s just a … cannon?

The U.S. Marine Corps Recruit Depot plans to do some training exercises at their base in the Midway area of San Diego from about 8 a.m. to noon. During that time, the base will be setting off some ceremonial cannon fire and playing warning messages over the loudspeaker, the MCRD said.

Both may be heard by civilians up to 20 miles away depending on atmospheric conditions, the MCRD said in a noise advisory to the public. That would be as far north as Solana Beach, as far south as the U.S.-Mexico border and as far east as El Cajon — a pretty large chunk of San Diego.

NBC 7 Meteorologist Sheena Parveen said due to monsoonal moisture this week, conditions may be just ripe enough to get that sound traveling.

“When the air is more humid, it is less dense (more buoyant), so sound would travel faster and farther,” Parveen said.

San Diego is not unfamiliar with loud and often unexplained booms. Sometimes it’s military training, such as Wednesday’s event. Other times it is weather- or earthquake-related. And, sometimes, there is never an answer at all.

At least this time, we have a heads up.