DENVER (CBS) – As ocean temperatures warm, rain and snowstorms become more intense, but may also come less often, according to distinguished senior science Dr. Kevin Trenberth at the National Center for Atmospheric Research.

Those are changes the people who fight wildfires across the nation have noticed.

“The climate is changing. I mean if you look at the last 100 years the average temperature has increased, if you looked at the last 30 years the average temperature has increased,” said Rod Moraga, a wildfire behavior analyst.

Don Whittemore is a fire incident commander with the Rocky Mountain Incident Management team and he has battled blazes for a long time.

“When I first got into firefighting 20 some years ago, Colorado was kind of jokingly referred to as the asbestos state,” Whittemore said, “Meaning that we just didn’t have fires and if we did have one it was an outlier. It was a rare event triggered by a weather anomaly.”

(credit: CBS)

(credit: CBS)

Now Whittemore believes climate change is making fires bigger, pointing to fires that used to last just a few days now burning for weeks or months.

It all started with the Hayman Fire in June 2002.

“That was like a wakeup call for Colorado firefighters that, ‘Oh, wait a minute, our past experience is not necessarily a predictor of what we’re seeing on the ground and what we might expect,’ ” Whittemore said.

COLORADO’S WEATHER CENTER: Watch more reports from the CBS4 special “The Science of Climate Change”

The Hayman Fire burned 133 homes. It was followed by the Fourmile Canyon Fire in 2010 which destroyed 169 homes.

“Since then we’ve had High Park and Black Forest and one or two others that have eclipsed as both the most destructive, but have really reset what it means to have a large fire along the Front Range,” Moraga said.

He was one of the first firefighters on the scene of the Fourmile Canyon Fire. He said there is no longer a wildfire season.

“We would plan for the summer months, especially on the Front Range,” Moraga said. “But we have seen over and over that some of our most destructive fires are in the shoulder seasons, whether it be late winter or early spring when we have our chinook winds and things like that.”

CBS4 Meteorologist Dave Aguilera (credit: CBS)

CBS4 Meteorologist Dave Aguilera (credit: CBS)

That intensity means firefighters are changing the way they approach wildfires.

“When all the elements that we need for a large fire are in place, you can put all the people you … all the firefighters, all the resources you want — they’re not going to put that fire out,” Moraga explained.

“Because of what we are seeing in the intensity of these wildfires now, it’s not a reasonable expectation anymore that we are going to put them out and protect every home,” he went on.

Whittemore and Moraga are both part of a film called “Unacceptable Risk” which tries to share the message that lives may be more important than extinguishing a fire.

“Those types of decisions might mean that more homes are lost,” Whittemore said. “But I’ll tell you I’ll sleep at night when I know that everybody has gone home and everybody in the public is safe. But if I lose a firefighter against an unacceptable, unwinnable fight, I won’t sleep at all.”

Wildfire Resources

– Visit’s Living With Wildfire section.

Wildfire Photo Galleries

– See images from the most destructive wildfires (Black Forest, Waldo Canyon, High Park and Fourmile) and largest wildfire (Hayman) in Colorado history.