Some residents on Montreal's West Island were shaken early Tuesday morning by a weather phenomenon known as a "frost quake." 

Dollard-Des Ormeaux resident Samantha Koury was woken at around 2:30 a.m by two loud noises.

"It sounded like a really big bang, like something fell on the floor in the house. And then there was another loud bang like something fell on the roof," said Koury. "We literally felt a huge shaking of the floor."  

The phenomenon — technically called a cryoseism — happens when water underground in caverns and pockets freezes very quickly, putting pressure on the surrounding earth and rock. 

Frost Quake

A "frost quake" can crack the ground and cause it to shake — feeling very similar to an earthquake. (CBC)

“The pressure grows until it breaks out and is released. That's the big boom. It's all that energy,” said David Phillips, a senior climatologist at Environment Canada.

Phillips says a "frost quake" could crack the ground and cause it to shake — feeling very similar to an earthquake.

He says a similar event can also happen when water collects on flat roofs.

"It will freeze expand and then crack with a boom," said Phillips.

Some West Islanders took to Twitter reporting hearing a loud boom overnight.

Learn more about cryoseisms tomorrow on CBC radio's Daybreak Montreal Wednesday at 6:40 a.m.