A fast-growing wildfire in Colorado forced 11,000 people from their homes at least briefly on Sunday and threatened popular summer camping grounds beneath Pikes Peak, whose vistas helped inspire the patriotic tune "America the Beautiful."

Live summit video from the 14,115-foot (4302 m) peak showed plumes of dark smoke billowing in the air, and a cog railway that ferries tourists up the side of the famous mountain was shut down because of the wildfires.

The blaze in the Pike National Forest, known as the Waldo Canyon Fire, has consumed about 2500 acres (1,012 hectares) since Saturday and triggered evacuation orders for 11,000 people from Colorado Springs and nearby towns, fire officials said.

"This is a very, very volatile situation," said emergency worker Rob Deyerberg at the fire joint information center.

The blaze was just one of 20 uncontrolled fires raging in US states on Sunday, mostly in the West, stoked by wind and triple digit temperatures in some areas. A fresh blaze in neighboring Utah forced an estimated 1500 people from their homes in that state, officials said.

Of those evacuated in Colorado, about 6200 people were cleared from Manitou Springs, which is often used as a base for travel to Pikes Peak, fire department spokesman Dave Hunting said. That evacuation order was later lifted on Sunday evening as winds calmed and stopped driving flames in that direction, while others remained in place.

Authorities also ordered residents to leave Green Mountain Falls, Chipita Park and Cascade, according to the fire incident command. No buildings had been lost to the fire as of Sunday evening, but the flames could threaten houses if the wind shifted, Deyerberg said.

El Paso County spokesman Dave Rose said the fire was burning two miles (3.2km) from the base of Pikes Peak, billed as the most visited mountain in North America. Flames were also visible in a heavily wooded neighborhood of upscale homes just south of the Garden of the Gods, a park in Colorado Springs that is popular with rock climbers.

The Waldo Canyon blaze came as firefighting resources were stretched by the monster High Park blaze west of Fort Collins, which officials now estimate has destroyed 248 homes since it was ignited two weeks ago. Another Colorado fire charred 21 homes on Saturday.

The High Park Fire - the second-largest on record in the state and its most destructive - has so far consumed 83,205 acres (33,672 hectares) in steep canyons. Sparked by lightning, it is blamed for the death of a 62-year-old grandmother in her mountain cabin.

"This fire continues to be persistent and find new areas that it can burn," incident commander Bill Hahnenberg said.

FRESH UTAH EVACUATIONS

In Utah, a fire that erupted Saturday evening destroyed 30 structures and pushed residents from their homes in the rural communities of Fountain Green and Indianola on Sunday, and forced a 24 km closure of state highway 89.

Fueled by gusty winds, the Wood Hollow fire has ballooned rapidly to 30,000 acres (12,140 ha) since it started in the foothills near Fountain Green, about 161 km south of Salt Lake City, Interagency Fire Center spokesman Don Carpenter said.

An exact cause of the fire was under investigation, although Carpenter said it was caused by somebody. Evacuations were ordered in three small towns and some rural subdivisions.

Sanpete County Sheriff's Deputy Eric Zeeman said around 1500 people had been evacuated, adding that it was hard to give an exact number because the fire had spread rapidly and the area included permanent residences and part-time dwellings. Officials earlier estimated 2500 people had been evacuated.

The fire has burned up over a mountain ridge through grass, sage, pinion juniper and alpine firs, and by midday was burning down north-facing slopes into a small valley, Carpenter said. At least one structure was destroyed.

"Everything is so dry and the temperatures are so high, it doesn't take much to have it go," he said, adding that about 64 firefighters were fighting the fire, with additional crews on the way. A PV-2 air tanker was providing air support.

Further north, crews were still battling the Dump fire, 56 km south of Salt Lake City. It was 40 per cent contained on Sunday, U.S. Forest Service fire information officer Kim Osborn said.

The 6023-acre (2437 ha) fire was started Thursday by target shooters and had earlier forced the evacuation of nearly 600 homes. Evacuation orders there were lifted on Saturday after keeping residents away about 30 hours.

On Sunday, Osborn said the fire was burning on a ridge a good distance from any structures, but fire managers were closely watching for shifting afternoon winds. 

- Reuters