What was that large boom near McHenry early Monday morning?

Shortly before 5 a.m. Monday, McHenry resident Kay France heard “one of the loudest booms” she’d ever heard in her life.

She hadn’t been getting much sleep with the storm – it was keeping her dogs up – and she was concerned enough to head outside to make sure one of her neighbors’ homes hadn’t been struck by lightning.

Lightning likely was the culprit, France learned.

The National Weather Service recorded a lightning strike – meaning lightning hit either the ground or something else – at 4:51 a.m. Monday in Johnsburg, meteorologist Jake Petr said.

What made the occurrence less common was the time of day and time of year.

—  National Weather Service meteorologist Jake Petr

The McHenry Township Fire Protection District didn’t receive any call about the strike, so if it did hit in Johnsburg, it didn’t cause a fire, said Battalion Chief Mike Majercik, who also heard the boom when waking up for his Monday morning shift.

Another strike was recorded at 4:38 a.m. in the area between Marengo, Harvard and Woodstock, and a couple occurred in Boone County, including one at 4:19 a.m. near Garden Prairie, Petr said.

The strikes were part of a line of thunderstorms that moved through the area as part of a larger rain system overnight Sunday into Monday, Petr said.

It wasn’t a lot of strikes for a circumstance like this one, but Petr said what did make the occurrence less common was the time of day and time of year.