BOULDER, Colo. — David Myers knew it was time to leave when he looked out into the forest and spotted bright red flames towering skyward. Then came a blinding cloud of smoke and a deafening roar as the fire ripped through the wilderness.

"You can hear just this consumption of fuel, just crackling and burning. And the hardest thing is ... you couldn't see it because at the point the smoke was that thick," he said.

Myers was among about 3,500 people who desperately fled the fire after it erupted in a tinder-dry canyon northwest of Boulder on Monday and swallowed up dozens of homes. Residents packed everything they could into their cars and sped down narrow, winding roads to safety, encountering a vicious firestorm that melted the bumper of one couple's van.

Myers said Tuesday afternoon that people told him they believed his house was destroyed. He said while he's sure he will experience "a varied level of emotions" about losing it, he remembers how he felt when fleeing the wildfire.

"All that really matters to us was my wife and I getting each other, getting the dogs, and getting out of there," Myers said. "We grabbed a couple of things, but when we look around, and we go, 'What should I take?' it all seems pretty irrelevant."

Authorities said Tuesday night they counted 92 structures that have been destroyed and another eight that have been damaged. It's unclear how many were homes.

Gov. Bill Ritter declared a state of emergency Tuesday as officials nearly doubled the fire's estimated size to more than 7,100 acres, or 11 square miles, based on better mapping. At one point, the plume from the fire could be seen in Wyoming, 90 miles to the north.

Authorities investigated reports that the fire started when a car crashed into a propane tank. They are also trying to figure out why an automated phone alert system failed for two hours during the evacuation, forcing authorities to go door-to-door to search for people in harm's way.

The fire caused no known injuries as residents appeared to get out of the area in time. But many spent Tuesday in shelters wondering if their homes still existed. Boulder County Sheriff Joe Pelle said nine volunteer firefighters were among those who lost their homes.

Winds pushed the fire through three canyons where disease, drought and beetles that burrow under the bark have killed pine trees. The so-called bark beetles have killed more than 3.5 million acres of trees in Colorado and southeastern Wyoming, and the dead trees are seen as a significant wildfire threat.

Gusty winds hampered firefighting Monday, and a squadron of firefighting planes was grounded much of the day Tuesday because smoke covered the canyonlands and obscured targets. A mix of cold and warm air sandwiched smoke over the area, but eight tankers were cleared to take off later in the day after the inversion began to clear.

At least 200 firefighters, including crews from Wyoming and outside the region, were battling the wildfire. Crews managed to save the historic town of Gold Hill, including an Old West grocery store and structures once used for stagecoach stops.

Though westerly dry winds that spread the blaze Monday had eased Tuesday, authorities said no portion of the fire was contained. Boulder County sheriff's Cmdr. Rich Brough said the fire grew on the northeast and southeast flanks and burned more structures during the day.

Authorities planned to start posting the addresses of buildings destroyed on the Boulder Office of Emergency Management website Tuesday night to start letting people know the fate of their property. It will be at least two days before anyone is allowed to go home, Brough said.

Some of those forced out of their homes expressed frustration with not knowing what was going on.

"There's no information about anything. ... I am so frustrated," said Ronda Plywaski, who fled her home with her husband and their two German shepherds and spent the night at an evacuation center at the University of Colorado. "I just want to know if my house is OK."