COLORADO SPRINGS, Colorado (AP) - A wildfire burning near Colorado Springs has destroyed at least 360 homes, making it the most destructive in the state's history, authorities said Thursday.

El Paso County sheriff Terry Maketa said that deputies still haven't been able to verify the condition of 79 homes as the wildfire continues to burn. So it's possible the figure could rise even higher.

The fire was burning near where the Waldo Canyon fire burned 347 homes last year. It was previously the most destructive in Colorado history.

A separate Colorado wildfire to the south has destroyed 20 structures, including some in Royal Gorge Bridge & Park, and prompted evacuations of about 250 residents and nearly 1,000 inmates at a medium-security prison. To the north, another fire burned in Rocky Mountain National Park.

Wildfires also were burning in New Mexico, Oregon and California, where a smokejumper was killed fighting one of dozens of lightning-sparked fires.

Crews were so busy battling blazes across the West that the US Forest Service said on Wednesday that it was mobilising a pair of Defence Department cargo planes to help - a step taken only when all of the Forest Service's contracted tankers already are in use.

The fire near Colorado Springs, one of several that broke out on Tuesday along Colorado's Front Range, has prompted evacuation orders and pre-evacuation notices to between 9,000 and 9,500 people and about 3,500 homes and businesses, sheriff's officials said.

Some Colorado Springs residents were warned to be ready to evacuate, mostly because of a fear of flying embers spreading the fire into the state's second-largest city. Sheriff's officials also evacuated part of neighbouring Elbert County, including two camps with a total of about 1,250 children and adults.

Bits of ash and the smell of smoke drifted into Denver, about 60 miles (100km) to the north, where the haze blocked the sun.

No injuries or deaths have been reported, but El Paso County Sheriff Terry Maketa said officials were trying to confirm the whereabouts of one person reported missing on Wednesday. Firefighters tried to go where the person was last seen but were turned back twice because it was too hot, he said.

Sheriff Maketa said he was worried about those who chose to ignore evacuation orders and stay behind.

The Forest Service mobilised specially equipped Defence Department C-130s to drop slurry on wildfires in the West after all 12 of its air tankers were deployed. At least one was fighting the Black Forest Fire.

By law, the Modular Airborne Firefighting System - MAFFS - planes can be deployed only when all of the Forest Service's contracted tankers are in use. Around this time last year, the aircraft sat on runways when massive wildfires burned in Colorado and New Mexico.

In northeast California, Mr Luke Sheehy was fatally injured this week by part of a falling tree in Modoc National Forest. The 28-year-old from Susanville, California, was a member of the Redding-based California Smokejumpers - firefighters who parachute into remote areas from airplanes.

In New Mexico, a wildfire burning in the steep, narrow canyons of the Pecos Wilderness north of Santa Fe grew to more than 12 square miles on Wednesday. It was burning about 10 miles southeast of some small communities. Crews planned to build fire lines and clear out fuel in key areas miles ahead of the blaze in hopes of protecting the communities if the fire heads that way.

In southwestern New Mexico, firefighters were trying to keep a massive wildfire from reaching an old mining town whose 45 or so residents have been evacuated. That fire was burning in a mountainous area of dense forest.

Another fire sparked by lightning on Monday in Rocky Mountain National Park has grown to an estimated 400 acres (160 hectares) in area with trees killed by pine beetles.

The cause of the fire near Colorado Springs wasn't clear. The El Paso County sheriff said there were no reports of lightning on Tuesday.

Governor John Hickenlooper declared disaster emergencies on Wednesday for the Black Forest and Royal Gorge fires and a 60-acre (25-hectare) fire in rural Huerfano County, authorising a combined US$10.15 million (S$12.6 million) to help pay for firefighting and other costs.