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Mid-Morning Sonic Boom Startles Upper Valley Residents

Did you hear it?

An extremely loud noise that was heard from Norwich to Vershire — and perhaps beyond — shortly before 11 yesterday morning may have been a sonic boom, according to an official from the Lebanon Municipal Airport air traffic control tower.

Air Traffic Manager Braxton Freeman said he couldn’t say for sure whether the noise was indeed a sonic boom, the loud noise produced by the shock wave from an aircraft traveling faster than the speed of sound, or about 750 mph at sea level, according to an Air Force fact sheet.

But after he received an inquiry from the Hanover police dispatch and a curious resident, he put in a call to the Federal Aviation Administration traffic agency in Boston.

“They informed me that there were some F-15s working in the military operating area,” he said, “and they could have produced the sonic boom sound, but they can’t be positive.”

The Massachusetts National Guard announced last month that it would conduct F-15 training sessions in Vermont and New Hampshire in the coming weeks.

Police at the Hanover dispatch, which takes calls for 23 towns including Norwich , reported receiving about 15 calls related to the sound.

Residents in Norwich, Thetford and Vershire reported the sound to the Valley News, which was heard around 10:48 a.m.

Another person, Fairlee Selectboard Chairwoman Mary Daly, was in her Fairlee home talking on the telephone to a Valley News reporter when she heard the loud noise, stopping mid-conversation to exclaim she heard a “boom” outside.

Around that time, Norwich resident Jonathan Frishtick was also talking on the telephone at his house when he heard the “shuddering noise.” He went downstairs to check his oil burner, gas line and water heater (they were fine), went outside to see if the snow on his roof had unloaded (it hadn’t), and then checked the U.S. Geological Survey website to see if there were reports of an earthquake (there weren’t).

After calling the Norwich Police Department non-emergency line and learning police there had heard the noise but were befuddled, as well, he emailed a friend who’s a geologist who suggested it may have been a sonic boom.

“I was inside and I didn’t even think of a sonic boom, I thought more of some kind of impact, like a huge tree falling in the backyard, or some sort of impact,” he said. “That’s why I thought it was like a short duration earthquake, but ... I think it came in two parts. It wasn’t one rumble.”