DENVER -- A wildfire that started on a military training site in southeastern Colorado doubled in size in a day and has scorched 42,000 acres.

The fire, named The Bridger Fire, started at Fort Carson's Piñon Canyon Maneuver site in southeast Colorado, was reported at 1 p.m. Tuesday. Fort Carson officials said Wednesday that they believe lightning started the blaze in the Red Rock Canyon area of the 236,000-acre site.

Military officials said Thursday the fire crossed the Purgatoire River, a natural fire break, and is now burning in surrounding federal, state and private land

A Type II federal fire management team took over firefighting operations on Thursday. Three heavy air tankers assigned and operating from Jefferson County, two U.S. Army Blackhawk helicopters, and three Hot Shot crews were also helping fight the fire Thursday.

So far, there has been zero containment of the blaze. Eight nearby ranches are threatened, but none are destroyed.

Pilots who made several trips south to Colorado Springs said the heavy winds were noticed but did not deter their missions.

"So, it makes it very difficult. So you just kind of stay on the side and try to hurt it (the fire) a little bit," said Capt. Skip Alderson.

Fire retardant was mixed constantly at the air tanker base.

Already the amount used is well ahead of the 2007 summer wildfire season.

"The amount of about 19,000 for the whole year (2007). And we've actually surpassed that in two days," said Mark Michelsen, the Air Tanker Base Manager.

The 250 firefighters actively attacking the blaze had a tough time Thursday because of the high winds, which blew through steadily at 20 to 30 mph. Winds on Friday are expected to be significantly less at 5- to 15 mph, fire officials said.

Low humidity and high heat have also hampered efforts to control the fire, said Capt. Gregory Dorman of Fort Carson, which operates the site.

Piñon Canyon is located about 150 miles southeast of Fort Carson and is used for training of large-scale operations.

The blaze is burning on grass and pinon-juniper in the remote and rugged country. The site on the southeastern plains is dotted by canyons and is surrounded by miles of ranch land.

Rancher Steve Wooten said between 400 and 600 acres of his family's property had burned along the river, about 3.5 miles from his home.

Wooten estimated that strong winds caused the fire to spread by about two miles on Wednesday. He said cattle have been moving away from the fire and aren't in danger, but he acknowledged that it does hurt to lose any pasture land during a drought.

Wooten said firefighters will need help from Mother Nature to stop the fire's spread.

"Because it's so big, it's going to be so difficult for man and machine to shut this down," he said.

Smoke from the fire could be seen as far away as La Junta.

As a result of the the growing wildfire threat, the Rocky Mountain Area Coordination Center has increased the preparedness level for the five-state area which comprises Colorado, Kansas, Nebraska, South Dakota and Wyoming.

The Rocky Mountain Area Coordination Center said the lower elevations of southern and southeastern Colorado are at the highest risk for wildfires in the region.