The Kenow wildfire raging through southwestern Alberta has reached 42,000 hectares in size, according to the latest fire map released by the Government of Alberta, as it burned its way into the townsite in Waterton Lakes National Park and forced hundreds of people to flee.

A government release sent out Tuesday evening said 33,000 hectares were burning in Alberta, with the remainder of the fire just across the border in southeastern B.C., where the fire started after a lightning strike nearly two weeks ago.

Measured at just over 11,000 hectares on Monday morning, the blaze has quadrupled in size over the last two days.

"The fire is out of control," said wildfire information officer Leslie Lozinski at a news conference.

"It is classified as 'out of control' and it will probably remain out of control for sometime until we see a significant change in the fire behaviour," she added.

Fire crews contended with what Lozinski called "extraordinary" conditions Monday — extreme winds, low humidity and warm temperatures — as they fought to contain the blaze.

The fire has burned into the townsite in Waterton Lakes National Park, destroying the visitor's centre and forcing hundreds of people there and in surrounding areas to flee — some with no warning in the middle of the night..

Smoke billows in Waterton Lakes National Park Tuesday morning behind the historic Prince of Wales hotel, after the Kenow wildfire reached the townsite of Waterton overnight. Firefighters have managed to save the majority of buildings, including the hotel, so far but about 500 had been forced to flee the townsite and surrounding areas. (Wes Dewsbery)

On Tuesday, Lozinski said, the fire behaviour was less aggressive because of cooler weather, weaker winds and higher humidity.

"What's going to happen overnight, we don't know, but going into it, it's a little bit calmer than it was last night and we hope that it's going to stay that way overnight," she said.

The townsite of Waterton was evacuated on Friday. The community has a year-round population of only 105 but draws hundreds if not thousands of visitors a day in the summer.

The majority of buildings in Waterton — including the Prince of Wales Hotel — appear to be intact, fire officials said Tuesday.

The Waterton Lakes National Park visitor's centre pictured before and after it was ravaged by the raging Kenow wildfire. (Left: Bryan Labby; Right: Wes Dewsbery)

More than 50 members of the Calgary Fire Department had been assigned to protect the historic hotel, spending the night dousing the structure in water and retardant and extinguishing small spot fires.

"Firefighters worked tirelessly throughout the night to extinguish spot fires, monitor sprinkler protection and protect facilities," Parks Canada said in a release.

The Shell Waterton gas complex just north of the park is also being threatened by flames but crews have managed to protect it, officials said.

On Tuesday night, the Alberta government said firefighters working within Waterton had been relived by a second team and would continue to work with 17 fire trucks on site.

As of that time, there were about 135 firefighters, nine Alberta air tankers and 14 helicopters within the park.

Alberta Forestry had an additional 125 firefighters and 23 helicopters on standby, waiting for direction from the command team, the government said.

'We saw flames from our house'

The unexpected and rapid advance of the wildfire also forced hundreds of people in neighbouring communities to relocate as officials issued evacuation orders overnight.

About 500 people have been forced to flee the fire so far including Waterton's evacuation last week, RCMP Cpl. Curtis Peters said shortly before noon.

"I come home and I just see this wall of fire. I said, 'Oh my God, we gotta get out of here,'" said Jim Garner, 73, who says his family only received 20 minutes' notice to evacuate, when the fire was less than 25 kilometres from ranch near Waterton.

They escaped, as did their stallions who were in a locked barn — but their home and business for 31 years were reduced to blackened rubble.

READ MORE ABOUT GARNER'S NARROW ESCAPE | Rancher's farm destroyed by Alberta wildfire 'looks a bit like hell'

Riesah Prock and husband Herky Cutler said they were woken at 2 a.m. when RCMP knocked on their door in Twin Butte, just north of Waterton Lakes.

"We saw flames from our house as we looked out and, of course, a great deal of smoke," Prock told The Calgary Eyeopener. "For us to see flames from our house is remarkable. It had to be very close."

A helicopter takes off to battle the Kenow wildfire, which is spreading through Waterton Lakes National Park. (Sarah Lawrynuik/CBC)

Prock said she had been preparing for a possible evacuation all week, loading a "bug-out bag" with food, essentials and items that can't be replaced.

After leaving Twin Butte, the couple headed to the relief centre in Pincher Creek, where Prock said she saw other evacuees carrying blankets, books and household items.

The couple is now in Calgary after dropping most of their valuables in a storage locker. Prock said she is happy to be in the city to "breathe some fresh air" after weeks of smoky conditions in the communities around Waterton Lakes.

"Yesterday it felt like someone had a barbecue and left a fire going in our living room," said Prock.

'We're being rained down on by ash'

Jared Pierson, who lives close to Waterton, drove to just outside the park gates on Monday night, saying he could feel the heat and hear the crackle of the fire.

"This is crazy. You can hear the fire roaring. We're being rained down on by ash. You can feel the heat of the fire as the wind is blowing. You can feel the heat of the fire coming down the highway," he said in a video he shot from the road.

"Since we've been here, looks like things are getting worse."

"We got a lot more than we bargained for," he told CBC News.

How the evacuation orders unfolded

The first of the evacuation orders was issued without warning for parts of the Municipal District of Pincher Creek just after 10 p.m. MT Monday. An estimated 150 residences were affected.

RCMP officers went door to door with Parks Canada staff to alert residents they needed to leave their homes, a process that Peters said went smoothly.

Cardston County — which has a population of nearly 4,500 — declared a state of emergency shortly after 1 a.m. Tuesday. More than 50 homes were affected.

The town of Pincher Creek — which has a population of just over 3,600 people and lies about 45 km from the park's boundary — was not placed under a state of emergency.

<a href="https://twitter.com/hashtag/Kenowfire?src=hash">#Kenowfire</a> made a shocking 15 km run OVERNIGHT. Thoughts w our fire colleagues at <a href="https://twitter.com/ParksCanada">@ParksCanada</a>. <a href="https://twitter.com/CWFIS">@CWFIS</a> <a href="https://twitter.com/WatertonLakesNP">@WatertonLakesNP</a> <a href="https://twitter.com/hashtag/Waterton?src=hash">#Waterton</a> <a href="https://twitter.com/hashtag/ABfire?src=hash">#ABfire</a> <a href="https://t.co/Y5exFnrzjK">pic.twitter.com/Y5exFnrzjK</a> —@ChristiansonAmy

On Tuesday morning, Pincher Creek Mayor Don Anderberg said an evacuation plan was being formed for the town should flames encroach.

"Hopefully it doesn't come to that but the fire was not supposed to be where it's at today, either," Anderberg said.

"I want to assure you everyone is working on the citizens' behalf and trying to keep on top of things."

Close to 4 a.m., residents of Canada's largest reserve, the Blood Reserve, also began evacuating.

"Blood Tribe Police are notifying Fishcreek residents in Zone 1 to evacuate and those in Zone 3 are on Notice."<a href="https://twitter.com/hashtag/Wateron?src=hash">#Wateron</a> <a href="https://twitter.com/hashtag/WatertonFire?src=hash">#WatertonFire</a> <a href="https://t.co/frxLisYKXr">pic.twitter.com/frxLisYKXr</a> —@arnelltf

The reserve is divided into zones, and Zone 1 — the southernmost zone — was under evacuation order, while Zone 3 — just north of Zone 1 — had been put on notice. An estimated 180 people were affected.

"That fire spread quite rapidly," said Oscar Cotton, the Blood Tribe emergency services director.

"A number of units of the local indigenous police force have been going door to door. They are confident at this point that everyone who was in potential danger has sought safety."

Change in weather coming

Dan Kulak with Environment Canada says the weather has been dry and warm in southern Alberta recently, but change is coming in the next few days.

"Some precipitation is expected to move in, and some little cooler weather, but unfortunately it's going to be a bit little longer — basically tomorrow night, Wednesday evening through Thursday, before any significant rainfall will be happening in the area," he said.

Kulak says until then there will be spotty showers, but they are hoping to see up to 15 mm in the southwest corner of Alberta in the next couple of days.

Winds gusting over 60 km/h out of the southwest helped push the fire east on Monday. Tuesday's winds have shifted, bringing in cooler air, Kulak says. The winds are coming from the northeast, which could help blow the fire back onto itself.

An offshoot fire about 800 hectares in size is also threatening the Castle area, which is being battled with helicopters, air tankers and heavy equipment.

This map shows the general location of the Kenow wildfire, which started nearly two weeks ago after a lightning strike in the Flathead Valley in B.C. and spread over the border into the Waterton Lakes National Park in southwestern Alberta. (CBC)

Evacuation centres