JASPER, Alta. -- About 1,000 tourists and outdoor enthusiasts have been evacuated from the picturesque Maligne Valley in the Alberta Rockies due to a large wildlife, a Parks Canada spokeswoman said late Friday.

Lightning is believed to have sparked what is being called the Excelsior fire, which flared up Thursday and grew to about 50 square kilometres by Friday.

Kim Weir of Parks Canada said favourable weather conditions had slowed the growth of the out-of-control blaze, but she warned the fire could continue to expand as weather conditions change over the weekend.

Parks officials began an evacuation of the valley on Thursday, using helicopters to ferry out back-country hikers and campers and escorting day-use tourists in a convoy down smoky roads in the area.

Some who were in campgrounds not near the blaze were told to stay put on Thursday night and leave the next day.

"The Maligne Valley evacuation is now complete," said Weir. "We have everyone out and they're safe and sound. Everything went very smoothly."

She noted that no tourist facilities were at risk and crews had set up sprinklers to protect buildings in the popular Maligne Lake area.

Maligne Lake itself and its iconic Spirit Island, a tiny clutch of trees surrounded by a ring of majestic mountains, three glaciers and pristine blue water, are 15 kilometres away from the blaze.

In addition, the Jasper townsite was considered a safe distance away, although Weir noted that the region was under a heavy blanket of smoke.

She said while the rest of Jasper National Park is still open for business, she warned tourists headed for the park to be mindful of the significant smoke issues in case they are a concern for people with health conditions.

Weir said the plan of attack is to monitor the fire's behaviour and if necessary, create containment lines where blazes would be deliberately set to impede its ability to spread; what Weir called "fighting fire with fire."

"Buckets of water from a helicopter aren't going to do a whole lot," she said. "If need be, we have helicopters that can bucket little parts of the fire and we can call in air tankers as well. However, the fire is large enough and in complex-enough terrain that ... we cannot get people on the ground as of yet."

Parks Canada crews were fighting the fire on Thursday and Friday, and another 40 firefighters from Manitoba were expected to arrive on the weekend.