A window rattling ‘explosion’ heard Wednesday, Dec. 10 in several Ladysmith neighbourhoods may have been a sonic boom, but a Canadian ariforce spokseperson said there were no Canadian jet fighters on the West Coast that day.
“It was a powerful enough blast that it virtually rattled the dishes in the cupboard,” said David Milne, who lives in the 800 block, Craig Road. “It actually shook the house.” Several of his neighbours stepped out of their houses at the same time to determine what had caused the noise.
Milne, who was talking to a friend in Courtenay shortly after the boom was heard here, learned that the same phenomenon had been experienced there, and the event was widely reported on the Around Town Facebook page, including one report from Crofton. “I’m in Crofton and we heard-felt it here too,” said Linda Prowse.
Other reports came in from Roberts Street and Fourth Avenue; from South Davis Road; and from Saltair. Placed on a map, the reports all fall close to a straight line between Crofton and Courtney.
Sonic booms occur when aircraft break the sound barrier, that is, when they travel faster than the speed of sound: 1,225 kilometres per hour.
At that point the sound waves become compressed into the shape of a cone, trailing the plane. Where that cone intersects with the ground along the flight path, a sonic boom occurs.
It ‘fills out a narrow path on the ground,’ says a Wikipedia description of the phenomenon. This path is called the ‘boom carpet.’ The faster the aircraft is travelling, and the higher, the narrower the boom carpet and the louder the sonic boom.
That the reports came in from a relatively straight line along a flight path from Crofton to Courtenay, corroborates the suggestion that it was a sonic boom.
That they were reported at almost the same time could be explained by the fact that a fighter jet can travel at speeds over 1,900 kph, which would take it from Ladysmith to Courtenay in about four minutes.
But Cpt. Alexandre Cadieux, a spokesperson for the Canadian air force, said there were no CF-18 Hornets on the West Coast that day, and that the CF-18 is the only Canadian miliatry aircraft capable of supersonic flight.
