Originally published June 9, 2011 at 6:46 a.m., updated June 9, 2011 at 9:08 a.m.
Fire crews in Arizona were bulldozing containment lines and setting backfires Thursday in hopes of gaining some control over a massive fire that has forced thousands from their homes and could take out the electrical grid supplying power as far east as Texas.
The 607-square-mile blaze, the second-largest ever seen in Arizona, is expected to reach the power lines as early as Friday. If the lines are damaged, hundreds of thousands of people in New Mexico and Texas could face rolling blackouts.
By early Thursday, the fire was "within probably about a half a mile" of the transmission towers, Sgt. Richard Guinn of the Apache County Sheriff's Office told NPR.
"The engineers tell me that whenever radio towers or transmission towers like that are exposed to extreme heat ... it creates stress weakening in the steel, so there is the possibility of damage to these towers," Guinn said.
The fire prompted Texas-based El Paso Electric to issue warnings of possible power interruptions for its customers in southern New Mexico and West Texas.
The company uses two high-voltage lines to bring electricity from the Palo Verde Nuclear Generating Station west of Phoenix to the two states. Losing the lines would cut off about 40 percent of the utility's supply, possibly triggering the rolling blackouts among its 372,000 customers.
Fire crews were hopeful that they could slow the flames Thursday if the weather forecasts pan out. After days of driving winds — including gusts of up to 50 mph — there was no high-wind warning issued for Thursday.
"Trying to contain something that large that's moving that fast because of the wind has been a challenge for firefighters," said Susan Zornek, fire information officer at the Rocky Mountain Incident Command Center.
Some 2,000 firefighters from across the country were helping battle the blaze, which officials say is "zero percent contained." A second major wildfire burning in southeastern Arizona was considered 50 percent contained.
Residents remaining in two towns — Springerville and the neighboring community of Eagar — that lie in the wildfire's path were ordered to evacuate their homes Wednesday after a spot fire popped up on the northwestern edge of the Wallow Fire.
Officials feared that the fire might hook around a bulldozer line and a burned-out area and race toward Springerville. Apache County sheriff's deputies and other law enforcement officers went house to house in the town looking for any residents who hadn't left.
At Reed's Lodge along Springerville's main street, Daric Knight was still there late Wednesday afternoon to make sure no embers landed on the building's wood shingles. His family has owned the lodge for decades.
"I've seen lots of fires, but nothing like this," he said.
The blaze has blackened about 389,000 acres and destroyed 11 buildings, primarily in the Apache-Sitgreaves National Forest. No serious injuries have been reported.
Fire spokesman Jim Whittington said at a briefing Wednesday night that the fire grew on the northwestern side because of driving afternoon winds but that an updated acreage figure wouldn't be available until later Thursday. He said firefighters planned to assess the area, particularly around the mountain resort community of Greer, and would know then whether any additional structures had burned.
Firefighters spent the past two days trying to create a line where they could defend the towns. They used bulldozers to scrape off vegetation and hand crews to remove other fuels. The line hadn't been breached, but officials were still worried about spot fires.
Crews on the ground have had help from more than a dozen helicopters. A 747 super tanker was expected to arrive Thursday.
"This fire [has] generated a lot of smoke," said Guinn of the Apache County Sheriff's Office. But instead of rising and blowing away, it has "tended to lay down and hug the ground like a fog," preventing tankers from seeing exactly where to lay fire retardant and water.
The blaze, burning in mainly ponderosa pine forest, was sparked May 29 by what authorities believe was an unattended campfire.