The Green Ridge fire near Camp Sherman in central Oregon is nearing 100% containment. Its been burning away for ten days after a lightning strike got it going on July 31.
Though the fire has been heading away from Camp Sherman and the Metolius river, naturally people in the area have been concerned about its spread -- now up to 1,500 acres, according to the latest official fire info.
Since my wife and I are part owners of a cabin on leased forest service land, Friday evening I decided to attend a fire status meeting for residents and visitors at the charming Camp Sherman Community Hall.
It was great to get a first-hand report on how the fire fighting efforts are going. In short, very well.
Personnel and equipment, such as helicopters, are being shifted to higher priority fires. There have only been two minor firefighter injuries, not counting lots of bee stings. The fire made a run to the east that was caused by wind-driven spot fires, but that is pretty much under control.
After the Fire Guy (didn't get a name) made his presentation, a Q & A session ensued. Several people wanted to know what "containment" meant. I'm glad they asked those questions.
I've had a vague idea about what it means when someone says, "The Whatever Fire is 30% contained," but I didn't really understand the notion of containment. I got educated some by the Fire Guy.
One questioner was confused by how it was possible for the Green Ridge fire to expand from 1,150 to 1,510 acres while the percent containment went from 50% to 75%. How could the burned area get bigger while so much progress was made on containing it?
The answer is that "containment" refers to the perimeter of a fire, not the area. If the perimeter is 10 miles, and containment lines are present on 7 miles, then the fire is 70% contained. But the fire still could be spreading via the uncontained 3 miles.
Fire Guy explained that containment lines can be established roads, natural barriers (like a river), or hand-constructed lines. I believe he said that the inside of the line has to be blackened, burned, before a line is considered a genuine containment line.
Also, mop-up operations have to be completed before a perimeter section is called "contained."
This includes watering-down hot spots near the line so embers can't be blown over it. Thus even though a line has been dug, it won't be considered part of the containment percentage until the mopping up adjacent to the line is complete.
Regarding how a fire is contained, Fire Guy stated the obvious: you don't want to be in front of a rapidly-spreading fire. So those fighting it start by anchoring the bottom of the area being burned, then work to contain the edges. Containment of the front of the fire comes last.
(Those who want to get into some geekiness of what "containment" means should read George Rebane's post, "Wildfire Containment Percentage: Say What??!!" Including the comments.)