The estimated size of the fire that burned through Yakima and Benton counties toward the Hanford nuclear reservation has more than doubled to 273 square miles.
The fire spread little on Monday, and the perimeter also held steady through Tuesday afternoon, according to the Northwest Incident Management Team assigned to the Range 12 Fire.
But once the smoke cleared enough for a helicopter to fly the perimeter of the fire with a global positioning system, a better estimate of the size of the fire was made. Fire officials increased the estimate from 110 square miles to 273 square miles late Monday.
A 117-mile line had been established around the fire perimeter by Tuesday afternoon. Firefighters continued to bolster it, widening it in places.
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The fire was just 20 percent contained Tuesday, but a large area had been burned on Rattlesnake Mountain and nearby land on the Hanford Reach National Monument to keep the fire from spreading to Benton City or the Hanford nuclear reservation.
Firefighters sacrificed the mountain, which is part of one of the last shrub steppe ecosystems in the Columbia Basin, to prevent a repeat of the 24 Command Fire in June 2000. That wildfire burned the mountain and spread across Hanford, threatening radioactive waste storage areas, and destroyed 11 homes in Benton City.
A red flag fire warning was issued for the Mid-Columbia on Tuesday because of gusty winds and low humidity as a dry, cold front moved through the area.
The incident command team was concerned that established fire perimeter lines could be threatened. However, no fire had spread outside the perimeter by early evening, and no flames were spotted by early Tuesday evening within the fire footprint, which includes some spots with vegetation still standing.
Firefighters continued patrolling the fire perimeter to search for any places where the fire was smoldering and watch for potential flare ups.
The fire started Saturday on the Yakima Training Center and spread south initially. Changing wind patterns then pushed it east toward Hanford and Benton City. By Sunday, it was burning between highways 240 and 241.
No cause has been determined.
No houses were considered threatened Tuesday, but earlier, the fire threatened 250 homes.
Crews fighting the fire have included 404 people, three helicopters, 34 fire engines and four bulldozers. Crews have come from as far away as Medford, Ore., to help fight the fire.
A temporary flight restriction is in place after a drone interfered with firefighting operations from the air over the weekend.