With an estimated 845,000 hectares of B.C. forests burned since April 1, the BC Wildfire Service says it's "safe to say we're on track for this to be the worst fire season on record."

"It's very much an estimate at this point, but given where we're at in the season, that number is certainly going to increase," said chief fire information officer Kevin Skrepnek Tuesday.

B.C.'s worst fire season on record was in 1958, when 855,000 hectares burned.

The cost of fighting wildfires so far this year sits at $309 million, which is specific to the wildfire service and not inclusive of other agencies involved. That makes this fire season the most costly since 2009, when the province spent $382 million on the wildfire service.

"Without knowing how the rest of the summer is going to play out, from a weather perspective, it's tough to know where we're going to land in terms of costs for the wildfire service specifically," Skrepnek said.

The largest fire currently burning is the Henceville-Riske Creek fire, about 60 kilometres southwest of Williams Lake, which is estimated to be at 212,000 hectares in size. The next largest is the Elephant Hill fire in the southern Cariboo, estimated at 168,000 hectares.

"Our priority remains public safety, first-responders' safety, and support to local authorities and First Nations," said Chris Duffy, executive director of Emergency Management BC.

Duffy said about 9,300 people are currently on evacuation order, with another 30,750 on evacuation alert.

"We still ask for the public's vigilance. There's still significant (fire) potential for a number of weeks ahead," Duffy said.

An estimated 71 residences have been lost to forest fires, as well as 118 outbuildings, three commercial buildings, and 117 other structures.