LAPORTE, Colo. — Firefighters on Sunday were fighting wildfires that have spread quickly in parched forests in Colorado and New Mexico, forcing hundreds of people from their homes and the evacuation of wolves from a sanctuary.

The Colorado fire, burning in a mountainous area about 15 miles west of Fort Collins, grew to more than 31 square miles within about a day of being reported and has destroyed or damaged 18 structures.

Strong winds, meanwhile, grounded aircraft fighting a 40-square-mile wildfire near the mountain community of Ruidoso in southern New Mexico. Crews were working to build a fire line around the blaze, which started Friday and has damaged or destroyed 36 structures.

It wasn't immediately clear how many of the structures lost were homes. "We're still trying to take a tally," Kerry Gladden, public information officer for Ruidoso, said late Sunday afternoon.

In Colorado, the fire sent up heavy smoke, obscuring the sun and creating an eerie, orange dusk in the middle of the day. The smell of smoke drifted into the Denver area and smoke spread as far away as central Nebraska, western Kansas and Texas.

The latest New Mexico fire is smaller than the Whitewater-Baldy fire – the largest in the state's history – but it's more concerning to authorities because it started closer to homes, said Dan Ware, a spokesman for the New Mexico State Forestry Division. He said the number of Ruidoso evacuees was in the hundreds, but he didn't have an exact figure.

Gladden said preliminary evacuations could be issued for some areas closer to town due to wind shifts.

Karen Takai, a spokeswoman for the Ruidoso fire crews, said smoke is heavily impacting the community of Capitan, about 5 miles to the northeast. She said Capitan and others could also face evacuation.

"Any communities around this fire have the potential of being evacuated," she said. "If I lived in Capitan, I definitely would be prepared. Don't wait until the sheriff's office comes knocking at your door and tells you to evacuate."

Elsewhere Sunday, firefighters were battling a wildfire that blackened 6 square miles in Wyoming's Guernsey State Park and forced the evacuation of between 500 and 1,000 campers and visitors. Cooler weather was helping firefighters in their battle against two other wildfires in southern Utah.

In Colorado, authorities sent nearly 1,800 evacuation notices to phone numbers but it wasn't clear how many residents had to leave. About 500 people had checked in at Red Cross shelters. Larimer County Sheriff Justin Smith said there was an unconfirmed report of a person unaccounted for, but he wouldn't elaborate.

Authorities say it's the worst fire seen in Larimer County in about 25 years. It spread as fast as 1 1/2 miles an hour Saturday, skipping over some areas but burning intensely in trees in others. Flames were coming dangerously close to deputies who were telling some residents to evacuate, Smith said.

Kathie Walter and her husband helped friends several miles away evacuate from the Colorado fire on Saturday. When they got home, they were surprised to get a call warning them to be ready to evacuate just in case. But Walter didn't want to wait.

"Smoke was coming in hard. We could not see flames or orange or black smoke. But we didn't need to see anymore. We just said `Hey, let's get out of here,'" she said.

They evacuated with their five cats and two dogs. They had a head start. After a wildfire in the area last year, they had left two suitcases packed in their garage.

Elaine Mantle and her family got a call to evacuate their Bellvue home at 5:45 a.m. Sunday. It took about 30 minutes for them to get out and reach a spillover shelter at the Budweiser Event Center in Loveland. Evacuees gathered there for a fire briefing, sipping coffee and eating bananas and powdered doughnuts, in a large gymnasium-like space.

It was the Mantles' first evacuation in the 25 years that they have lived in the mountains, and they were grateful to be safe.

"We're all here, we're all OK. Our neighbors are all here. We feel good," Mantle said.

The blaze also forced the evacuation of 11 wolves from a sanctuary near the fire. KUSA-TV in Denver reported that 19 wolves remained behind at the sanctuary, which has underground concrete bunkers known as "fire dens" that can be used by the animals.

The fire is the latest to hit Colorado's drought-stricken Front Range. In May, a fire set by a camper's stove charred 12 square miles in the same Poudre Canyon area. In March, a fire sparked by a prescribed burn 25 miles southwest of Denver killed three people and damaged or destroyed more than two dozen homes.

Eight air tankers – including two from Canada – and several helicopters were on the scene to help fight the blaze.

Authorities say they're competing for resources that have been diluted by several wildfires burning across the West.

"Resources are thin right now," said Nick Christensen of the Larimer County Sheriff's Office. "We are trying to get more of everything at this point."

Meanwhile, the speed at which the fire has spread has dashed any hopes of containment for the time being.

"These folks are doing everything they can, but Mother Nature is running this fire," Smith, the sheriff, said.

In New Mexico, the mix of timber, dry grass and the steepness of the slopes were making the firefighting efforts more difficult.

The fire was burning in steep, rocky, inaccessible terrain in the White Mountain Wilderness of the Lincoln National Forest, which is home to Smokey Bear, who became the nation's symbol of fire prevention in the 1940s.

More than 300 firefighters were battling the blaze with help from three large air tankers, three heavy helicopters and three Blackhawk helicopters. There were also 100 National Guard troops in Ruidoso.

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Associated Press writers Thomas Peipert in Denver and Amanda Lee Myers in Phoenix contributed to this report.

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  • This image provided Aug. 11, 2012 by Chips Fire shows a wildfire inside Northern California's Plumas National Forest. Strong winds and low humidity have helped this wildfire increase to nearly 47 square miles.(AP Photo/Chips Fire)

  • Flames burn near Highway 48 and HW 38 junction east of Drumright, Okla., on Saturday, Aug 4, 2012. Emergency management officials have ordered evacuations of homes in several areas as wildfires burn across the state. The Oklahoma Department of Emergency Services says no injuries have been reported. (AP Photo/Tulsa World, Tom Gilbert)

  • Fire burns above Hidden Valley Ranch where fire crews worked to halt progression of the Taylor Brige Fire on Thursday, August 16, 2012, near Cle Elum, Wash. The Taylor Bridge Fire has forced hundreds to evacuate and has burned dozens of homes near Cle Elum, Wash. (AP Photo/seattlepi.com, Joshua Trujillo) MAGS OUT; NO SALES; SEATTLE TIMES OUT; MANDATORY CREDIT; TV OUT

  • In this photo taken Tuesday, Aug. 14, 2012, flames surround a house on a hillside above Bettas Road near Cle Elum, Wash. A spokesman for the Washington state Department of Natural Resources said the house survived the fire because of the defensible space around the structure with the placement of the driveway and the lack of trees and brush up against the house, preventing flames from reaching it. Firefighters are still working to control the Bridge Taylor Fire and said that it's 25 percent contained. (AP Photo/Elaine Thompson)

  • In this photo taken Aug. 9, 2012 and released by the San Diego County Fire Authority, Cal Fire firefighters attack a blaze near Chihuahua Valley Road in Northern San Diego County. A wildfire ignited by lightning continues to burn out of control in the highlands northeast of Warner Springs, Calif. State fire Battalion Chief Nick Schuler says the 900 acre fire was active overnight and was only 5 percent contained early Friday. (AP Photo/Kevin Pack/San Diego County Fire Authority)

  • As smoke rises behind, firefighter Jose Barajas hefts his pack as he gets his equipment ready Wednesday, Aug. 15, 2012, near Cle Elum, Wash. Crews fighting the large blaze in central Washington hope to increase containment levels by Wednesday evening, but are keeping a wary eye on weather conditions later in the week. The fire burning near Cle Elum has burned dozens of homes and caused about 900 people to evacuate. (AP Photo/Elaine Thompson)

  • A house is engulfed in flames near Highway 48 and HW 38 junction east of Drumright, Okla., on Saturday, Aug 4, 2012. Emergency management officials have ordered evacuations of homes in several areas as wildfires burn across the state. The Oklahoma Department of Emergency Services says no injuries have been reported. (AP Photo/Tulsa World, Tom Gilbert)

  • Smoke fills the area as Logan Renner, 17, walks through ashes toward an opening in what was his family's home Saturday, Aug. 4, 2012 in Luther, Okla. While residents of one Oklahoma town sifted through their charred belongings Saturday to salvage what they could after a roaring wildfire that may have been deliberately set, residents in two other towns were being ordered to evacuate their homes. The fire near Luther, which is about 25 miles northeast of Oklahoma City, destroyed nearly five dozen homes and other buildings before firefighters were able to gain some measure of control Saturday.(AP Photo/The Oklahoman, Jim Beckel) TABLOIDS OUT

  • Smoke is visible from Tie Siding, Wyo., as a wildfire burns northwest of Fort Collins, Colo., on Saturday, June 9, 2012. The cause of the fire is not yet known. (AP Photo/Laramie Daily Boomerang, Andy Carpenean)

  • This undated photo provided by the McFaddin National Wildlife Refuge shows wildfires burning in the refuge. An official with the U.S. Fish and Wildlife Service says multiple wildfires have closed the Texas wildlife refuge on the Gulf coast. (AP Photo/McFaddin National Wildlife Refuge)

  • This photo provided by the Boise National Forest shows the Springs Fire, 4 miles east of Banks, Idaho, along Highway 17. So far it's burned more than 600 acres, but fire officials said Tuesday, Aug. 7, 2012 that it is 30 percent contained. (AP Photo/Boise National Forest)

  • In this Sunday Aug. 12, 2012 photo provided by the Joshua Tree National Park, a 300-acre fire believed to have been sparked by lightning from Sunday's thunderstorms burns in Joshua Tree National Park east of Palm Springs. A 220-acre blaze is near Vallecito in San Diego County, also believed to have been sparked by lightning from Sunday's thunderstorms, is burning out of control but no homes are nearby. (AP Photo/Joshua Tree National Park)

  • In this Aug. 12, 2012 photo provided by the Wyoming State Forestry Division, a column of smoke rises from the wildfire burning about 10 miles south of Glenrock in central Wyoming. The fire has burned about 6,500 acres since it was discovered last Friday. Officials say the fire was about 20 percent contained and showed little activity on Monday. (AP Photo/Wyoming State Forestry Division)

  • This photo provided by the U.S. Bureau of Indian Affairs shows the Alpine Lake Fire burning Monday, Aug. 13, 2012, in the Shoshone Forest on the Wind River Indian Reservation in central Wyoming. The fire forced the helicopter evacuation of five people from a backcountry outfitter camp on Tuesday. They were safely extracted. Firefighters have not been able to suppress the fire so far because it is located in extremely rugged country. (AP Photo/U.S. Bureau of Indian Affairs)

  • Smoke billows from the Little Bear fire in southeastern New Mexico near Ruidoso, Saturday, June 9, 2012. Spanning only a few acres on Wednesday, the Little Bear fire began to grow Friday as spot fires formed outside established fire lines due to windy conditions. By Saturday morning, about 10,000 acres had been charred northwest of the mountain community of Ruidoso. (AP Photo/Roswell Daily Record, Mark Wilson)

  • A house is engulfed in flames near Highway 48 and HW 38 junction east of Drumright, Okla,, on Saturday, Aug 4, 2012. Emergency management officials have ordered evacuations of homes in several areas as wildfires burn across the state. The Oklahoma Department of Emergency Services says no injuries have been reported. (AP Photo/Tulsa World, Tom Gilbert)

  • Flames leap into the air as area firefighters fight a wildfire on Cemetery Road east of 120th on Friday, Aug. 3, 2012, east of Norman, Okla. A wildfire stirred by high winds sweeping through rural woodlands just south of the Oklahoma City area has set at a number of homes on fire. (AP Photo/The Oklahoman, Steve Sisney) TABLOIDS OUT

  • A horse grazes in a pasture along Colorado County Road 80C in Larimer County, Colo., as smoke billows from a wildfire Saturdaym June 9, 2012, northwest of Fort Collins, Colo. The cause of the fire is not yet known. (AP Photo/Laramie Daily Boomerang, Andy Carpenean)

  • Smoke billows from the Little Bear fire in southeastern New Mexico near Ruidoso, Saturday, June 9, 2012. Spanning only a few acres on Wednesday, the Little Bear fire began to grow Friday as spot fires formed outside established fire lines due to windy conditions. By Saturday morning, about 10,000 acres had been charred northwest of the mountain community of Ruidoso. (AP Photo/Roswell Daily Record, Mark Wilson)

  • A truck drives down the road as smoke billows in the background from the Little Bear fire in southeastern New Mexico near Ruidoso, Saturday, June 9, 2012. Spanning only a few acres on Wednesday, the Little Bear fire began to grow Friday as spot fires formed outside established fire lines due to windy conditions. By Saturday morning, about 10,000 acres had been charred northwest of the mountain community of Ruidoso. (AP Photo/Roswell Daily Record, Mark Wilson)

  • A sign posted to a tree in Featherville, Idaho on Wednesday, Aug. 15, 2012 expresses gratitude for firefighters who are battling the 100-square-mile Trinity Ridge Fire burning less than five miles away. Residents have been warned they will likely have to evacuate. (AP Photo/Jessie L. Bonner)