Steff Mason was taken aback when a huge low-frequency rumbling shook the Robson Community School on Thursday morning.
“It didn’t sound like explosion,” Mason, an education assistant at the school, told Castlegar News. “It wasn’t a bang, it was long and dragged out.”
“It scared the pants off us.”
Mason took to social media looking for an explanation. Dozens of other people were reporting hearing the mystery sound, which some said sounded like a landslide.
“It was crazy loud, around lunchtime,” said Jennifer Beharrell. “It scared me a little because I thought that it was something drastic. Louder than any thunder I’ve heard before.”
But local emergency officials and weather forecasters knew nothing that might have caused it, and an earthquake website didn’t register anything.
Turns out, the noise was caused by explosions from road building several miles away— and an unusual set of atmospheric conditions.
“We had a road-building crew blasting along Merry Creek,” says Gerald Cordeiro, the development supervisor for Kalesnikoff Lumber. “The sound people heard was coming from a rock blast that carried across the river towards Robson and Pass Creek.”
The road crew is building a road to a cut block in the Merry Creek area.
Cordeiro says a combination of somewhat unusual conditions— the blasting was in hard rock, which more efficiently bounced the sound— and low cloud cover helped reflect the noise towards the communities across the river from the road building.
He says there was nothing unusual about the size of the blast or the procedures the crew was using.
“We were surprised by the amount of reaction from the communities, so we asked the contractor to hold off any more blasting for a few days so we can get word out about the work being done,” he says.
Cordeiro says Kalesnikoff’s contractors will be doing some more blasting the week of November 5, during regular working hours. He says the company will also take steps in the future to make sure the public is informed of any blasting taking place that may be heard by residents.