LOS ALAMOS, N.M. - Driven by swirling wind of up to 55 mph, fire rolled from block to block in abandoned Los Alamos on Thursday after burning scores of homes down to their foundations and rolling over explosives bunkers in the town where the atomic bomb was built.
Firefighters doused still-standing homes with water as orange flames and billowing smoke rose over the town. Whole neighborhoods were reduced to smoldering ruins, with everything from trailers to mansions going up in smoke in a fire that was deliberately set to burn brush at Bandelier National Monument.
Park Superintendent Roy Weaver was placed on leave Thursday pending an investigation.
Fire spokesman Juan Rios said the number of evacuees increased to 20,000 to 25,000 people Thursday, including residents of the Espanola Valley northeast of Los Alamos and Abiquiu Grant township north of Los Alamos.
The wildfire first reached Los Alamos on Wednesday - forcing the evacuation of the entire town - and exploded in size from 3,700 acres to 18,000 Thursday, fanned by blowtorch winds so strong they made parked cars sway and blew open building doors.
''I can't believe how many homes are gone,'' said Don Shainin, a fire battalion commander from Albuquerque who came to Los Alamos to help out.
At the lab, flames burned trailers and portable buildings, rolled past concrete bunkers containing explosives, and came within 30 yards of a plutonium storage facility. But lab officials insisted that dangerous materials were protected in fireproof facilities strong enough to withstand the crash of a 747.
''We can assure the country and New Mexico that our nuclear materials are safe,'' said Energy Secretary Bill Richardson, a former New Mexico congressman.
By nightfall, the fire had destroyed an estimated 260 homes and damaged 20 others on the northern and western parts of town, said Bill Lehman, spokesman for Los Alamos County. The count included townhouses and duplexes under the same roof.
Rep. Tom Udall, whose district includes Los Alamos, said earlier that federal officials estimated 300 to 400 were burned.
With the fire spreading and thousands of people evacuated from Los Alamos and nearby White Rock, finger-pointing had already begun.
The fire had been set May 4 by the National Park Service to clear brush near Bandelier National Monument, but it raged out of control in the dry, windy conditions. Weaver, Bandelier's superintendent, could not be reached for comment on whether he had seen a special National Weather Service forecast faxed to the park beforehand that said fire-growth conditions were at their highest.
Federal authorities pledged to investigate.
''Somebody made a mistake and obviously we have to find out who,'' Sen. Pete Domenici, R-N.M., said as he visited the fire zone.
Weaver, who gave the administrative go-ahead for the fire, was placed on administrative leave with pay pending the outcome of an independent investigation.
National Park Service spokesman Rick Frost said it's not unusual procedure to place an employee on leave while the agency investigates an administrative decision.
Weaver has worked for the Park Service for 33 years, including the past 10 in charge of Bandelier. A Park Service official from Arizona will step in at least temporarily to oversee Bandelier National Monument.
Crews working with hand tools and bulldozers worked feverishly to protect homes by clearing away vegetation and cutting firebreaks ahead of the flames. Helicopters dropped water on the fire, while airplanes bombarded it with pink fire retardant.
''Our biggest concern continues to be the unpredictability of the winds,'' Lehman said.
Los Alamos, 70 miles north of Albuquerque, is essentially a company town for the weapons laboratory, which employs 7,000 people at buildings scattered throughout the city. The town is on a mesa, altitude 7,600 feet.
The fire came out of the Jemez Mountains to the west and moved northeast, torching the west and north sides of the city.
As the sun rose Thursday, brick fireplaces and chimneys were the only things remaining of some homes. A basketball hoop remained intact on one driveway, its net singed but still hanging outside a destroyed house.
On the western edge of town, homes were burned to the ground on a mesa overlooking Los Alamos Canyon. The canyon's towering ponderosa pines could be seen through the scorched shells of homes that had been valued at more than a quarter-million dollars.
About 150 National Guardsmen were called in to keep people out of the evacuated zones and prevent looting.
Many of the people forced to evacuate from White Rock on Thursday had already fled Los Alamos.
Kirk Christensen and his wife had taken in four Los Alamos families this week. But when the fire advanced on White Rock, they had to load their camper and head into a sea of cars crawling down the highway for Santa Fe, where they planned to camp outside a friend's house.
''We weren't ready down here,'' Christensen said. ''We were the refugee center for our friends.''
About 50 miles east of Los Alamos, over the Sangre de Cristo Mountains, a 200-acre blaze sparked by an airplane crash burned near the resort area of Storrie Lake, state Forestry Division spokeswoman Terri Wildermuth said.
About 75 firefighters were battling the blaze, and homes were being evacuated, Wildermuth said. There was no immediate word on fatalities in the airplane crash.
Another fire burned about 100 acres south of Cloudcroft, in the southern part of the state, Lincoln Zone dispatch spokesman Rick Hartigan said. The communities of Sacramento and Weed were ordered evacuated, said fire information officer Gwen Shaffer.
The fire, reported around 5 p.m., burned in old-growth ponderosa pine and mixed conifer trees in the Lincoln National Forest. Three air tankers bombarded the blaze with pink fire retardant, while a dozen firefighters worked the blaze on the ground, he said.
About 30 miles to the north, Lt. Gov. Walter Bradley toured the area around an 8,600-acre fire in the Ruidoso area that had forced hundreds of homes to be evacuated early this week.