A wildfire burning in Jasper National Park's Chetamon Mountain is now estimated to cover an area of around 6,000 hectares, Parks Canada said Monday evening.
An earlier estimate Monday pegged the fire at about 8,000 hectares.
A lightning strike on Sept. 1 started the fire, which grew from 400 hectares Saturday to 1,500 hectares Sunday.
Warm, dry and windy weather Sunday pushed the fire eastward, but the region had overnight rain, the agency said. A Monday evening news release said precipitation between three and five millimetres around the Jasper townsite and the wildfire gave the opportunity to reassess critical power lines for Atco and TransMountain as well as reassess the fire size.
It noted the size will be variable throughout the coming days.
Katie Ellsworth, a fire management officer with Parks Canada, said Monday the fire posed no threat to the town of Jasper, about 360 kilometres west of Edmonton.
The fire was about 15 kilometres north of the town, Ellsworth said.
"We've been really challenged by the rugged and complex terrain," Ellsworth said of the Chetamon area.
"The significant smoke conditions are making it challenging for bucket operations and it's making it challenging to access some of those larger water resources like water tankers from our partners in Alberta," she said.
Parks Canada has closed Talbot Lake, Talbot Lake day use area, Snaring and Celestine Lake roads and the Snaring and Snaring overflow campgrounds.
Ellsworth said they're planning to close the Wabasso campground as early as Tuesday morning.
Power in Jasper went out again early Monday morning, after a brief outage was restored Sunday evening, wildfire officials said.
Jasper Mayor Richard Ireland warned people that the power outage could be extensive.
"The message to residents and visitors is that in the face of uncertainty, be prepared. I don't know how long 'extensive' might be, and we don't know yet, all of the capacity issues so there is just such uncertainty in this unfolding situation."
As of Sunday, eight helicopters were flying over the fire to drop water on the flames; 77 Parks Canada firefighters and personnel, as well as other pilots and contractors, were working to prevent the fire from spreading to high-risk areas, the agency said.
A heatwave that settled over much of Alberta the past week has not helped with fire conditions. Several areas in Alberta set new daily maximum temperature records on Sunday including Calgary and Edmonton but cooler temperatures are setting in around Jasper. Rain is expected today and later this week.
The agency's top priority is protecting critical infrastructure and adding more helicopters to the suppression efforts, officials said. That includes protecting culturally significant sites, such as the Moberly Homestead, which is part of Métis history.
The fire spread to the Atco, TransMountain and Canadian National Railway lines, officials said.
Parks Canada closed Snaring and Celestine Lake Roads and the surrounding areas, including nearby campgrounds, to ensure public safety during fire operations.
The agency also restricted aircraft take off and landing at the Jasper air strip, citing public safety.
Fire spreads to Jasper, Alta., power supply
Before Jasper lost power Sunday evening, Alberta Emergency Alert had advised residents to prepare for a possible power outage, including filling up their vehicle's fuel tank, as gas stations rely on electricity.
Ireland, who held a joint press conference Sunday with fire officials, urged residents and people visiting the area to adhere to restrictions and other advisories and closures.
Ireland also told residents to make sure their cellphone batteries are charged.
Chetamon Mountain wildfire
"Our message, still, is one of preparation," Ireland said.
No evacuation order has been issued.
The municipality had been working with Atco and Parks Canada in the event of a power outage.
Amanda Mattern, regional manager for Atco Electric, said Monday the utility was switching to emergency generation to critical sites like the hospital, fire hall and the municipality's emergency crisis centre. Atco will look to extend power to homes and businesses in the coming days.
Ireland did not anticipate the need for an evacuation as of Sunday afternoon. But new visitors may eventually be restricted from coming into Jasper, and resources may need to be directed to helping people currently visiting exit the community, he said.
"At this time, we cannot offer visitors the full services they would typically expect, at this uncertain time."
Hugo Sanchez, an Edmonton resident visiting the area, said it looked like the entire mountain was in flames.
"It's devastating to see all the fire," Sanchez told CBC News. "[Crews] are trying to put it out. They can't — but you see they're trying their best."
Air quality statement issued
Environment Canada issued a special air quality statement for the Jasper National Park area Monday morning, because wildfire smoke continues to cause poor air quality and reduced visibility.
People may experience increased coughing, throat irritation, headaches or shortness of breath, the statement says, adding that children, seniors and those with heart or lung disease are particularly at-risk.
Environment Canada advises people in the area to consider taking precautions to reduce their exposure to wildfire smoke.
Most of Alberta, including the Jasper National Park area, is under fire advisories, restrictions or bans.