Forest fires in Canada's western province of British Columbia intensified further on Saturday, doubling the number of people under an evacuation order to 35,000 from a day earlier, as authorities warned of difficult days ahead.

The province declared a state of emergency on Friday to access temporary authoritative powers to tackle fire-related risks, as out-of-control fires ripped through interior British Columbia and partially shut down some sections of a key transit route between the Pacific coast and the rest of western Canada, and destroyed many properties.

"The current situation is grim," Premier Daniel Eby told reporters on Saturday, saying some 35,000 people are under an evacuation order, and a further 30,000 are under an evacuation alert.

Eby said the province is in dire need of shelter for evacuees and firefighters and ordered a ban on non-essential travel to make more temporary accommodation available.

British Colombia has experienced strong winds and dry lightning in the past few days due to a cold mass of air interacting with hot air built-up in the sultry summer. That intensified existing forest fires and ignited new ones.

"We are still in some critically dry conditions, and are still expecting difficult days ahead," said Jerrad Schroeder, deputy fire center manager at the Kamloops Fire Centre.

By Friday, an out-of-control fire in the south of the province grew more than a hundredfold in 24 hours and forced more than 2,400 properties to be evacuated. The fire was centered around Kelowna, a city some 300 kilometers east of Vancouver, with a population of about 150,000.

The fires moved so rapidly on Friday that the number of people under evacuation order grew from 4,500 to 15,000 in an hour, while another 20,000 were under evacuation alert. The province currently accounts for over a third of Canada's 1,062 active fires.

The flames have already destroyed several structures in West Kelowna and authorities have been warning that the province could potentially face the worst couple of days of the fire season this year.

(With input from Reuters)

(If you have specific expertise and want to contribute, or if you have a topic of interest that you'd like to share with us, please email us at nature@cgtn.com.)