Power outages likely as 'bomb cyclone' forms off B.C. coast, meteorologist says

Forecasters are warning of hurricane-level wind gusts as a "bomb cyclone" forms off the coast of Vancouver Island late Tuesday.

A cyclone is the term used when masses of warm and cool air collide to create spiralling winds, with forecasters saying the "bomb" portion of the name refers to a rapid pressure drop of over 24 millibars (the unit used to measure air pressure) in 24 hours.

The bomb cyclone currently forming 400 kilometres west of Tofino, B.C., could see a pressure drop of 60 millibars over a 24-hour stretch in the centre of the storm — which forecasters called highly unusual for B.C.

Wind warnings issued Monday evening cover the entirety of B.C.'s coast, with Environment Canada saying easterly wind speeds of 90 km/h, gusting up to 120 km/h, will develop starting Tuesday afternoon in coastal areas.

Brian Proctor, an Environment Canada meteorologist, said that strong easterly winds will rip through B.C.'s coastal valleys, and there will also be outflow winds coming from the B.C. Interior due to the strong low-pressure system off the coast.

"We're likely to see power outages. I wouldn't be surprised to see B.C. Ferries having some shutdowns as well [Tuesday] through the afternoon, evening hours," Proctor told CBC News on Monday.

Armel Castellan, another meteorologist with the weather office, said that the strong outflow winds from the Interior that will arrive on Tuesday afternoon are something officials hadn't seen yet so far this season.

"When we talk about wind strength, we also need to talk about wind direction. And we consider that the first time we see a strong wind in a new direction as a time to be vigilant," he said.

"Because the forests — or certainly the trees that line our power cables, transmission lines — are going to be tested in a new way."

Proctor says that the bomb cyclone will also bring some rain and snow at higher elevations to much of coastal B.C. — though the amounts wouldn't be as much as an atmospheric river system that brought flash floods to the South Coast in October.

"If this flow is coming in 200 or 300 kilometres further to the east, we would be seeing tremendous impacts upon the inner South Coast and all of Vancouver Island," the meteorologist said.

A hurricane is described as a cyclone with sustained wind speeds of at least 119 km/h, according to the  Canadian Hurricane Centre.

Tuesday's storm is the second major windstorm to hit B.C.'s South Coast in a week, with one that hit last on Nov. 12 leading to hundreds of thousands without power.

Cliff Mass, a professor of atmospheric and climate sciences at the University of Washington in Seattle, categorized the wind speeds from the incoming storm as "hurricane-force" and said the storm would impact the entire West Coast of North America down to California.