Here's how many flights have been cancelled by WestJet, Air Canada due to extreme weather

More than 1,000 flights have been cancelled by Air Canada and WestJet over recent days, when winter weather first began impacting airport operations in Vancouver and beyond, stranding thousands during the peak holiday travel period.

In an emailed update from WestJet on Wednesday, the carrier said nine flights set to depart Thursday had already been called off and "cancellations are projected to increase."

The "critical factors impacting operations" included extremely frigid temperatures in Northern B.C. and Alberta, "de-icing limitations," the "cascading" effect of cancellations at YVR, and the ongoing cold weather in Vancouver.

There were 130 WestJet flights cancelled by 4 p.m. Wednesday, which followed 240 on Tuesday, 146 on Monday and 104 on Sunday – for a total of 620 over four days.

"The ongoing extreme cold weather warnings affecting Alberta and prolonged forecasted snow and weather events for regions across B.C. inclusive of, Vancouver Island, the Lower Mainland and the Okanagan are having a severe impact not only on our operations, but our staff and service partners who are battling frigid temperatures and extreme weather," the emailed update says.

"In Vancouver today and across last night alone, the weather prevented many of our staff and service partners from being able to get to work safely. Additionally, severe weather impacts continue to prove challenging as we work to stabilize our operations and facilitate mandatory crew rest requirements for safety."

The airline has outlined options for people who have travel scheduled and want to cancel due to the uncertainty. For those already impacted, information on how to proceed is available online.

Air Canada would not provide the number of cancelled flights, instead offering general information

"On average, Air Canada has approximately 935 flights departing every day throughout its global network. Since the beginning of December, Air Canada’s flight completion rate has been well above 98 per cent," a sposkesperson said in an email.

"Over the past five days which saw storms in Ontario and then in B.C., our flight completion rate dropped to 87.25 per cent"

Based on those numbers roughly 600 flights have been cancelled, which works out to an average of 119 per day.

The airline is implementing what it calls an "extended goodwill policy" for people who decide to cancel or reschedule their holiday travel plans.