Fire crews say no one was injured in a large blaze that consumed a number of townhomes under construction in northwest Calgary on Friday morning.

Flames were spotted at a condo complex in the community of Panorama Hills at just before 3 a.m.

By the time crews got there, the fire had fully involved two of the units, reducing one to a pile of rubble while the other has been heavily damaged.

Firefighters on scene were concerned about propane tanks stored between the units and they had to focus on hosing them down to keep them from exploding.

Crews also had Mother Nature on their side, with a strong westerly wind keeping the fire from spreading to neighbouring complexes.

"We got a bit of west wind going here," said CFD Battalion Chief Ernie Molineaux. "It carried the flames and heat to the east. The homes that were evacuated were on the west side. If it had been going the other way, it could have been a very different story."

They say about 20 people had to be evacuated from surrounding homes but should be allowed to go home later in the morning.

A resident who lives nearby says they were concerned about the safety of their own home. "I was really scared. I was praying the fire wouldn't get to our house. We just moved in recently and having spent all the money and trouble just to be told your house is burnt is a very painful experience."

Another resident, who was also roused by the raging fire, says they heard the glass in their windows cracking from the heat. "It was scaring the heck out of me. I thought they were going to blow in."

The townhomes involved in the fire were not occupied.

12 homes suffered damage from the fire, with the intense heat melting siding and breaking windows.

The fire department says that the houses that were destroyed were nearly completed and the owners were ready to move in.

One of those homes was destroyed while the other was severely damaged. Two more homes, in their framing stages, were also levelled.

There is no word on what caused the blaze.

Crews remain on scene to take care of hot spots.