OTTAWA, July 26 (Reuters) - Steady rain is likely to

help firefighters working to contain a massive wildfire that has

devastated parts of the western Canadian tourist town of Jasper,

authorities said on Friday.

Jasper is in the middle of mountainous Jasper National Park

in the province of Alberta. A huge fast-moving fire has damaged

or destroyed up to half the town's structures.

Parks Canada said between 10 mm and 15 mm of rain had fallen

on Thursday. "This precipitation will likely keep fire behavior

low for the next 72 hours," it said in a statement.

"Crews will take advantage of this time to make as much

progress as possible to suppress the wildfire and reduce further

spread. While rain in Jasper is a welcome sight, warm weather is

forecast and will increase wildfire activity."

Authorities have so far declined to give specific details of

how many buildings were lost in Jasper, which normally has a

population of around 5,000. Video posted to social media showed

entire blocks had been burned to the ground.

The town and park, which draw more than 2 million tourists a

year to this area of the Rocky Mountains, were evacuated on

Monday, when officials estimated there were up to 10,000 people

in the town and a further 15,000 visitors in the park.

Late on Thursday, authorities said crews had managed to

protect all of Jasper's critical infrastructure. This included

the hospital, schools and a wastewater treatment plant.

The Jasper Park Lodge, one of the largest hotels in town,

said it had suffered some damage but most structures remained

standing and intact. The 400-room residence is run by Fairmont,

a group owned by France's Accor.

The Trans Mountain oil pipeline, which can carry 890,000

barrels per day (bpd) of oil from Edmonton to Vancouver, runs

through the park. The operator said on Thursday there were no

signs of damage.

The federal government said in April that high temperatures

and tinder-dry forests meant this could be a catastrophic year

for wildfires in Canada.

The current fire could be one of the most damaging in

Alberta since a 2016 blaze that hit the oil town of Fort

McMurray, forcing the evacuation of all 90,000 residents and

destroying 10% of all structures there.