ST. CHARLES, Mo. – When firefighters attacked a house fire on Nancy Drive in 10 inches of snow and only 10 degrees outside, they say it seemed like a straight-forward house fire.

But Jan. 5, 2014 nearly turned deadly.

“We thought we had the fire put out,” remembers Firefighter Matt Mackley.

But as crews were putting out some remaining spot fires, “everything changed in an instant,” says Tim Kirchoff.

It's believe that when large sliding glass doors blew out on the back of the house, wind gusts of nearly 50 mph rushed in and stoked the flames, trapping four St. Charles firefighters in the basement.

All four eventually crawled their way to a window — escaping what investigators would later say had a 97% chance of fatality.

“I thought for sure that was it,” says Kirchoff who remembers crawling and groping his way to the window not sure he would find a way out.

The department is now using what they learned fighting the fire to train other departments about the dangerous of wind-driven fires that were once thought to only occur in high rise buildings.

But with fast burning synthetic furnishings firefighters say strong winds can cause typical house fires to “flash-over” faster and more dangerously.

Photos: Firefighters learn from wind-driven fires