MEDICINE HAT, Alta. - Evacuations were ordered in communities across southern Alberta and Saskatchewan on Tuesday due to grass fires from winds that Environment Canada warned could reach up to 100 kilometres an hour.

Two trains went flying and another caught on fire in southeastern Alberta; trucks went off the road on major highways; countless roads were closed due to thick smoke; and some buildings burned north of Calgary.

Late in the evening, officials in Lethbridge, Alta., issued an evacuation alert for one neighbourhood and said three crews were fighting a blaze in a coulee used as a dog park that is close to houses. Efforts were also being made to restore power to parts of the city where it had been knocked out.

Over in Saskatchewan, officials ordered a precautionary evacuation for the town of Leader, which has a population of nearly 900 people.

"We're not sure if it's going to hit here or not," said town councillor Albert Heck. "We really don't know how the fires are doing at this point. It's quite a few miles away yet, but a little bit of change in the wind and we could be in a problem."

He said residents had mostly gone to the neighbouring communities of Kindersley or Swift Current.

"The smoke is mostly going still south of town, so we don't have a whole lot of smoke here yet. So that's a good sign for us, because usually the way the smoke goes is the way the fire is going to go."

Provincial spokeswoman Kathy Young said the Emergency Management and Fire Safety branch was on the scene and co-ordinating the fire response and evacuation, while a rapid response team was dispatched to assist local fire departments.

Meanwhile, residents of the Sharp Hill neighbourhood in Airdrie just on the northern outskirts of Calgary and people near the town of Coleman in the Crowsnest Pass were also told to leave their homes.

As the evening progressed, Rocky View County announced on its Facebook page the Airdrie-area fire had been brought under control and crews were looking for hotspots.

"The situation is significantly improved," confirmed RCMP Cpl. Curtis Peter, but he said there had been some structural damage.

"One home has been totally lost. Another home has been partially lost and fairly significantly damaged, and a third has damage to outbuildings."

He said officials were unsure about when evacuees might be allowed to go home.

"They are working on checking the damage to infrastructure right now and then that'll be how they determine what happens next."

The flames and smoke prompted safety officials to close Highway 3 between Coleman and the British Columbia boundary.

Near Strathmore, Alta., Peter said a train caught fire near the Agrium Plant which in turn created a grass fire due to the extreme winds. He said the train did not derail and no injuries were reported.

Canadian National reported two trains did derail in Alberta, and the winds were being investigated as a factor.

Kate Fenske of CN said the first involved multiple cars south of Huxley, Alta., and the second happened west of Wainwright.

Both incidents involved cars carrying mixed freight, and there were no reports of spills or leaks of dangerous goods, and no reports of injuries.

Const. Chris Bilodeau of the Wainwright RCMP said five cars went over a high trestle bridge near the hamlet of Fabyan.

"It's over the Fabyan valley, which is pretty deep," he said. "It happened on the west side of the bridge, so only five cars made it onto the bridge. Those five cars fell off of the bridge and down into the valley."

Social media was also alight with reportings of vehicles being blown off the road, like the tweet of Riversdale Hey who said he'd "seen seven trailers flipped between Airdrie and Leduc. Lost a visor ... to boot."

Elsewhere, evacuations were also ordered on the Siksika First Nation, the hamlets of Hilda and Moon River Estates, and the town of Gleichen.

RCMP shut down Highway 41 in both directions due to poor visibility caused by smoke and people were being warned to avoid the area.

An evacuation was also ordered in Burstall, Sask., which has a population of about 300, and in the southern rural municipality of Deerforks.

There, some who stayed behind said the situation seemed to be improving as the night went on.

"Right now it's still windy, but there's a bit of improvement with the smoke," said resident Vipul Patel. "I see some vehicles, they are coming back."

Joseph Kwak, owner of the Burstall Hotel, said all his customers left after the evacuation was ordered, but he joked he would call them in the morning and tell them to come back.

"It's over, I think so," he said. "The smoke is gone."