Authorities in Ontario say keeping the Parry Sound 33 wildfire away from key infrastructure is their most important task as they deal with more than 140 fires burning around the province.

“Parry Sound 33 continues to be our top priority fire,” Bill Cole of the province’s Ministry of Natural Resources and Forestry told reporters Thursday.

The fire had grown to more than 11,000 hectares, or 110 square kilometres on Thursday. Its northeastern edge was said to be about 4.5 kilometres west of the Highway 69 portion of the Trans-Canada Highway.

A more immediate risk was the CN rail line west of the highway. Officials said crews were working to keep the flames away from the key rail link.

The fire’s trek toward Highway 69 had been slowed over the last few days by cloud cover and a shift in wind direction. Southwesterly winds were expected to return to the area Thursday afternoon, potentially fanning the flames back in the direction of the highway.

Cole said the fire was still showing “modest growth” but presenting “no imminent threat” to the highway, thanks in large part to the midweek weather conditions.

“We’ve been able to establish control lines around portions of the fire,” he said.

In some areas, crews are using a technique known as backfiring – setting small fires to burn out key sections of forest before the larger fire can get to them. This helps create a natural barrier to prevent the larger fires from spreading.

Local authorities say the highway will be closed if travel conditions become hazardous. If that were to happen, people in Sudbury and other northern communities would temporarily lose their quickest route to southern Ontario – with the nearest detour adding several hours of travel time.

Thirteen buildings are known to have been destroyed by Parry Sound 33. Cole said efforts were underway to contact the owners of those properties.

Evacuations and air quality concerns

More than 1,000 people in the area of the fire have been evacuated due to Parry Sound 33. The latest evacuations affected approximately 400 cottages and 30 homes in the municipality of Killarney.

Jim Rook, the municipality’s emergency management co-ordinator, said Wednesday that most of the cottagers had returned to their year-round homes, while permanent residents were mainly staying with friends and relatives.

“We’re quite confident that [for] our residents that have been evacuated … their properties are going to be safe,” he told CTV News Channel.

Evacuations were also ordered in the communities of Henvey Inlet and Key Harbour shortly after the fire broke out on July 18. Many Henvey Inlet residents have been staying in hotels in Sudbury, which is about 70 kilometres to the north but close enough that the smell of smoke from Parry Sound 33 lingers in the air.

Approximately 2,000 residents of the community of Alban, which is across the highway from the fire, have been warned that evacuations may be ordered there if the situation deteriorates.

The fire was also affecting air quality in the region. Environment Canada said Thursday morning that smoke was reducing visibility in Greater Sudbury, and could be harmful to human health anywhere it descended to ground level.

“If you’re smelling a bit of smoke but otherwise are not having any issues with it, then you can continue with your normal activity,” Dr. Maya de Zoysa, a respirologist, told CTV Northern Ontario.

“However, if you do notice that you’re getting irritation in your eyes or nose, or you’re noticing you’re coughing or having problems breathing, you should definitely go back indoors – and if it worsens, you should seek medical attention.”

Smoke was expected to be a continuing concern in areas downwind of Parry Sound 33 and other major fires, Cole said.

142 fires reported across Ontario

The fire has also dealt a blow to the region’s seasonal tourism area. Some businesses have been shut down as a direct result of the fire, while others have seen significant sales losses due to visitors staying away.

“We have 10 businesses that are affected very badly,” Rook said.

Approximately 280 firefighters from across North America are working to extinguish Parry Sound 33. Sixteen helicopters are part of the battle.

Retired firefighters have alsobeen brought in to provide support. Ten retired firefighters had been hired as of Thursday, with plans to increase that number to 56.

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There were 49 forest fires burning in northeastern Ontario as of late Wednesday night, 21 of which were considered to be out of control. Another 93 active fires were reported in the province’s northwest.

Other high-priority fires, according to Cole, include the Lady Evelyn fire cluster north of North Bay. That fire had reached 27,579 hectares as of Thursday afternoon and was not considered to be under control, but Cole said it did not appear to be expanding beyond its borders.

“That fire has not spread outside its perimeter for quite a few days now,” he said.

In northwestern Ontario, nine fires were discovered Wednesday night outside Fort Severn by an aerial patrol. The fires were described as being 40 kilometres away from Fort Severn and two to 200 hectares in size. Closer inspections were being planned, and firefighters would be sent to the area if needed, Cole said.

Most of Ontario’s major active wildfires are believed to have been sparked by lightning. The cause of Parry Sound 33 has not been determined.

With reports from CTV Northern Ontario’s Callam Rodya and Molly Frommer