SILVERTHORNE - A 91-acre wildfire ignited Tuesday on Buffalo Mountain in Summit County, joining a rash of blazes that have burned tens of thousands of acres statewide, threatening homes and forcing thousands to evacuate.

"Living in the mountains, we have a lot of benefits, but fire is one of the shortcomings that we have to deal with," Summit County Commissioner Dan Gibbs said at a public meeting Tuesday evening.

The Buffalo fire prompted the evacuation of 1,384 homes in the Mesa Cortina and Wildernest neighborhoods above 20 Grand Road, Summit Fire and EMS reported. Another 1,160 residences below 20 Grand Road were on pre-evacuation notice.

The area had received no lightning strikes, "so you can draw your own conclusions about the cause," Summit Fire Chief Jeff Berino said.

Air tankers, helicopters and ground crews were working to suppress the blaze, which was burning heavy timber and beetle-killed stands of trees, reported the National Interagency Fire Center in Boise, Idaho.

"We called air resources very early since this fire had 'air' written all over it," Berino said. "That made a significant difference."

Tuesday afternoon, Berino said 50 firefighters were battling the blaze, and 100 more were on their way from across the state.

"Things are looking really good around the two subdivisions at this time," said Jim Genung, incident commander from the Upper Colorado River Interagency Fire Management Unit.

While crews were "doing a bang-up job getting in there and holding things," Genung said, "the biggest factor to containing or holding this fire ... is the fuel breaks that were put in there over the past several years.

"After the bug epidemic that came through, several fuel breaks around those subdivisions were placed in there, and those fuel breaks right now are saving several thousand homes, probably, from having fire in them.

"We're a model for proactive wildfire prep," Gibbs said.

Those breaks helped save Susan and Herb Sebastian's rented condominium in Wildernest.

"This morning, I opened the sliding-glass door in the condo and smelled smoke," Susan said. "It didn't occur to me that it was a wildfire until the owner called us saying we were being evacuated."

The Houston residents grabbed a few essentials. A law enforcement official banged on the door, telling them to leave immediately.

"He said the fire was 2 miles up-wind from us," Herb said. "We were ready, so it wasn't too scary, and we didn't see flames until we reached the City Market in town."

Don Samuels' property is just north of the fire perimeter next to Eagles Nest Wilderness on Ruby Ranch. He said his community is at risk if the winds change direction.

"And because we're next to wilderness land, the Forest Service was not able to do as much fuel reduction as they did in Wildernest and Mesa Cortina," said Samuels, who planned to stay in his home but moved his horses from his pasture to a "wet, grassy area."

Under the Wilderness Act, the Forest Service cannot use chainsaws to clear trees, leaving areas such as Ruby Ranch susceptible to higher fire risk. So Samuels and many of his neighbors have established defensible spaces around their homes.

"We're absolutely aware of the risk we take living here," he said.

The fate of the Wilderness and Forest Service land to the north and west of Samuels' home is less certain than that of the subdivisions. Those areas could burn for a couple of weeks, "maybe even a month," Dillon District Ranger Bill Jackson said.

"Plan to see this fire from your back door for a little while."

The county issued an air-quality health notice for wildfire smoke, the Summit Daily News reported. Smoke was expected to settle into Silverthorne, Dillon and Frisco by Wednesday morning.

The wildfires come as much of Colorado is in drought. Nearly 8 percent of the state - including La Plata and Montezuma counties, where the 416 and Burro fires are burning - is in exceptional drought, the U.S. Drought Monitor's highest classification.

The 416 fire had burned 23,378 acres and was 15 percent contained Tuesday. Just west, the Burro fire had burned 2,136 acres.

A fire weather watch was issued for Thursday in a large swath of western Colorado, reported the National Weather Service in Grand Junction.

"New fire starts and existing fires may be difficult or impossible to control due to fast rates of spread," the watch says. "Outdoor burning is strongly discouraged."

A dense smoke advisory was issued for Tuesday evening until noon Wednesday along the U.S. 550 corridor north of Hermosa through Durango and down to the New Mexico line, as well as along U.S. 160 east of Hesperus through Bayfield.

"Colorado has allocated more resources for firefighting than any other state in the Rocky Mountain West," Gov. John Hickenlooper said in a statement. "We have seven interagency heavy air tankers fighting the Colorado fires and, through experience, we have learned how to integrate our state resources with our federal, county and municipal resources.

"We recognize the conditions are dry and hot. Public health and safety are the top priorities in fighting any fire. If you are in the fire zones, please follow safety procedures and directives. Our state agencies are here to support you. As we have proved time and time again, Coloradans are resilient."

Even as visitors, the Sebastians said, they feel that the best of the best are battling the blaze.

"The first responders here are the real pros in fire suppression and keeping the community safe," Susan Sebestian said. "We're very thankful for them."