The Bordeaux region in Southwest France has experienced many fires in the last few weeks that have burned a total of about 50,000 acres (20,000 Ha). Thinking that it will stop future fires, officials are building a large fire break three miles (5 K) long and about 1,000 feet (300 meters) wide.
In parts of the Western United States back in the 1960s building fire breaks was a common practice. Some were only one or two dozer blades wide scraped down to mineral soil, while others were wider. But in later decades firefighters realized that no firebreak is likely to stop a rapidly spreading blaze.
Fires become large most often because they are burning in copious amounts of vegetation (fuel) during strong winds. Under unusually hot, dry, and windy conditions burning embers are lofted into the air. As they are blown downwind they can ignite new fires, “spot fires”, hundreds of feet or even up to a mile away from the main fire. Usually these embers are small, but can be as large as tree branches or even a four-by-eight-foot sheet of plywood, both of which have come close to or even hit air tankers working over the fire.
Under extreme conditions nothing will stop a large fire unless it completely runs out of fuel over a very large area, or the weather changes. A 1,000-foot fire break can stop a slow moving fire, but not a conflagration of the type that wipes out dozens of structures.
Something that cannot be ignored is that removal of all vegetation can result in severe environmental damage.
In the United States land managers are now more prone to build fuel breaks. They do not attempt to remove all vegetation, but only reduce it to the point where it will slow the spread of a fire enough that firefighters, sometimes aided by aircraft dropping water or fire retardant, can safely move in close to the flanks, make a direct attack, anchor the heel, and work their way along the edges and eventually stop the head of the fire. Fuel breaks helped firefighters last year on the Caldor Fire near South Lake Tahoe in California.
The first video below describes the firebreak in France. The next one is an update on the wildfires in the southwest part of the country.
