BOULDER, Colo. -- The Flagstaff fire burning near boulder is now 90 percent contained, officials said Sunday.
By Saturday evening all but a small portion of the 300-acre fire's perimeter had been contained.
The remaining 10 percent is in very steep terrain on the southeast side of South Boulder Peak, said Sean Collins of the fire incident command team.
Crews have not been able to hike into that area, but incident commanders planed to continue attacking the area with water drops from a helicopter, Collins said.
Crews lit a 20-acre patch of green fuels behind the fire line about midday Saturday, sending black smoke above Boulder. The back burn helped fortify containment lines.
About 60 firefighters worked the fire, which is now in its fifth day. It is believed to have been started by a lightning strike.
"We had three crews and two engines up on the fire with also support from two helicopters and they continued to finalize the last piece of open line to get it as tied in as possible," Collins said.
Boulder police and fire spokeswoman Kim Kobel told the Daily Camera city leaders were grateful for the efforts of firefighters and the federal team.
"We just really appreciate a federal team coming," Kobel told the newspaper. "So many agencies came to our aid when we called them. We got the air support that we asked for right away. As we have seen from some of these other fires around Colorado, getting a jump a fire right away is really integral to getting it under control and stopping it from spreading into residential areas."
The neighborhoods nearest to the fire -- on Bison Drive and Pika Loop -- remain closed to everyone except residents.
Flagstaff Road is now open to the public, but firefighting vehicles are still traveling up and down the road so people are asked to keep the road clear.
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