CALGARY, Alberta, Dec 30 (Reuters) - Canada"s WestJet Airlines will cancel 15% of scheduled flights in January because the rapidly spreading Omicron variant of COVID-19 has left the airline unable to fully staff its operations, the company said on Thursday. The announcement from privately owned WestJet, headquartered in Calgary, Alberta, comes after a slew of North American flight cancellations due to surging coronavirus cases and brutally cold winter weather. read more There are 181 WestJet staff currently off work due to COVID-19, a 35% increase in recent days, company spokeswoman Morgan Bell said in an email. WestJet was operating around 450 flights a day - meaning 68 daily departures face cancellation - and Bell said warm weather destinations, international and domestic flights will all be impacted. "We could not have anticipated the rapid and unpredictable impact of the Omicron variant on our people and operations, coupled with prolonged frigid temperatures across Western Canada and global staffing shortages," WestJet Chief Executive Harry Taylor said in a statement posted to the airline"s website. WestJet said it will try to consolidate flights that will cause the least disruption, and notify travelers in advance. Rival Air Canada (AC.TO) has canceled approximately 4% of its flights over the past week although those most changes were due to adverse winter weather rather than coronavirus infections, the company said in an email. "While overall we have the crews to operate our flights, some of aviation"s third-party service and support providers have experienced operational constraints, which together with the difficult winter conditions, have affected the current schedule," Air Canada said. The airline will evaluate and adjust its 2022 route schedule as needed in response to the COVID-19 pandemic and travel restrictions, Air Canada added.