SATUS PASS — Firefighters were battling a large wildland fire near Satus Pass late Wednesday that shut down U.S. Highway 97.

The fire was estimated at 1,200 acres by Wednesday evening, when two water-dropping helicopters, at least four engines and dozens of firefighters were on scene. Smoke from the fire rose in a huge white column visible from as far as the Upper Yakima Valley.

By late afternoon, flames had jumped the highway and were burning on both sides of the road, according to the state Department of Transportation, which closed the road about 4 p.m. The fire was initially reported shortly before 11 a.m.

The fire is on the Yakama reservation, north of the summit of Satus Pass, the 3,107-foot mountain pass that marks the border between Yakima and Klickitat counties. It is a rugged area of forest and grassland.

There is no estimated time on the reopening of the highway.

Firefighters with the Bureau of Indian Affairs and the Department of Natural Resources are on scene and more are expected this morning.

Those on scene Wednesday had to contend with temperatures as high as 96 degrees and winds of 10 mph, according to the National Weather Service in Pendleton, Ore.

The weather service issued a red flag warning for the Yakima, Klickitat and Kittitas valleys from 3 p.m. today to 9 p.m. Friday. Low relative humidity and increasing winds are expected to aggravate fires in the area and could cause new fires to spread rapidly, the service said. The Valley could see wind gusts of up to 35 mph.

Temperatures were expected to cool to 61 degrees overnight, and increase to 97 today with winds anywhere from 5 to 7 mph, the weather service said.

The last major fire on Satus Pass was in September 2011, when the Monastery Complex Fire exploded, burning 3,600 acres and destroying more than 100 buildings, including 29 homes.

More than 700 firefighters were called out to the fire, which authorities suspect might have been started by a truck on Highway 97 that sent sparks into dry grass .