Combined fires force another evacuation.

Byline: Bill Bishop The Register-Guard

About 300 Camp Sherman residents were ordered Thursday to evacuate for a second time as the two fires of the B and B Complex burned together, generating a huge plume that threatens to re-create conditions that fostered a 10,000-acre run of fire on Wednesday.

The fire is burning actively six miles north of Camp Sherman and is moving northeast, away from the community, fire information officer Sarah Bickford said.

Nevertheless, wind, weather and fuel conditions are producing spot fires up to three-fourths of a mile in advance of the fire. With unpredictable conditions, fire officials ordered the second evacuation around 3:30 p.m. Thursday.

The fire spotted across Forest Service Road 12, which had been used as a major fire line guarding the east flank of the fire, Bickford noted. Fire officials said fire lines along Road 12 were key to their containment plan.

"It's a very significant development," Bickford said.

Highway 20 remains open but was closed for nearly two hours during the evacuation. Travelers should expect delays due to firefighting activities and the 45 mph speed limit, fire officials said.

Fire managers had hoped to keep separate the two fires of the B and B Complex because of the heavy load of large dead trees in the area between the fires and because the lava flow terrain would hamper the movement of crews and equipment in that area.

Their hopes collapsed late Wednesday along with a huge plume of smoke that pulled down with it a strong flow of air which pushed the fire four miles northeast in one hour, fire information officer Lori Hammer said. The fires were then only a mile or two apart.

Firefighters were forced to withdraw eastward and build additional fire lines against the possibility the fire's energy might build for another major run - as it did on Thursday.

Big fires often develop a huge, hot plume. A change in the atmosphere, a lack of fuel as the fire advances, or a combination causes the column to collapse - creating strong, erratic winds like those during Wednesday's four-mile run.

"There was really no stopping it," Hammer said. "Right before that happened, we removed all our fire teams (from the area between the fires)."

In one hour on Wednesday, the fire swept another 10,000 acres into the B and B Complex. After Thursday's run, the fire is now estimated at more than 70,000 acres. More than 2,200 firefighters are on the job.

The heavy fuel load between the fires sets the stage for another big fire buildup, with another potential for a huge plume and the possibility of another major run that might be difficult to stop, Hammer said.

Firefighters have been preparing for this scenario by overlapping fire lines along the road networks to the east of the fire lines protecting the community of Camp Sherman and areas north, Hammer said.

While they are confident the fire lines will hold, they were largely untested before Thursday's run, Hammer said.

On Thursday, evacuation was ordered for all areas along the Metolius River between Abbot Creek, near the Warm Springs Indian Reservation, south to Highway 20 - which included Camp Sherman, Bickford said.

Camp Sherman residents had been allowed to return Saturday after a 12-day evacuation. But fire managers urged those who returned to keep their cars packed up and ready to leave at a moment's notice.

Hammer said fuel and weather are keys to the developing situation.

It's not always the big trees that cause the biggest problems, she said. Sometimes it's the small things.

In the B and B Complex, fire managers estimate five to six tons of lichen hangs in the trees on every unburned acre. All of it is tinder dry. When embers fall on lichen, it quickly ignites a fire in the crown of a tree that spreads rapidly to nearby trees, sometimes far from the main fire in a process called "spotting."

The Booth Fire was spotting three-fourths of a mile ahead of itself as the plume collapsed on Wednesday. It repeated its long-distance spotting on Thursday.

"The spotting we have experienced, it has been a consistent characteristic of this fire," Hammer said.

A spotting fire keeps fire crews looking over their shoulders. Safety rules require one crew member to be assigned solely as the lookout, keeping track of weather and staying in radio contact with the fire base.

"With spotting, it makes it difficult to know. Is the fire in front of you or is it behind you? You definitely don't want to get caught in between," Hammer said. "When it gets too smoky and we can't see the spots, we pull the teams out."

Weather forecasts call for possible thundershowers, followed by a Pacific weather system late in the weekend - which is good and bad news for firefighting.

In the short term, southerly winds may bring rain in the thunderstorms moving up from California. As the weekend rain approaches, the winds will shift to westerly. In the mountains, shifting winds thwart plans for firefighting. Crews and equipment must move as the conditions dictate.

Meteorologist Mark O'Malley, of the National Weather Service in Portland, said the weekend rain is the first Pacific system of the fall.

"I can't say it's the beginning of the rainy period. There is a possibility next Tuesday or Wednesday there may be another system," he said.

Meanwhile, in heat and wind, the fire grows.

"The wind was playing havoc with us," said fire information officer Mick Mueller. "It is making for some unpredictability."