I found this and thought it a very good read... 
The fastest human cannot outrun fire
The fastest human cannot outrun fire
'Sort of leapfrogs itself':
Flames can race through a forest at up to 50 km/h
Julie Smyth
National Post
Saturday, August 23, 2003
At their worst, forest fires can hit speeds approaching 50 km/h, moving faster than any human, as they rip down forests and ravage communities.
As emergency workers rushed door-to-door warning people of the escalating fires in and around Kelowna, B.C., where 10,000 people have been evacuated, residents feared strong winds would help fuel the blaze.
Fires need three things to pick up speed -- steep slopes, strong winds and a lot of dry, small fuel, such as pine needles or dead grass. The Okanagan area is full of open space, hills and pine trees, making it a perfect feeding ground for a raging fire. When fires get hot enough, they move up into the crown of trees -- any part where the bottom of branches reach --where there is a lot of oxygen, thousands of flammable needles and thin branches, all the components of a fast fire.
"You can probably get up to about 10 km/h, but fires can travel faster than that because what happens is this wall of flame shoots up a lot of burning embers and needles from the trees and they can be blown in front of the fire and set fire to another [tree]. It sort of leapfrogs itself, then it goes on and on. Then the speed can double or triple," Michael Feller, associate professor in forest sciences at the University of British Columbia, said yesterday.
The speed of a fire is difficult to measure but there have been reports of up to 50 km/h, he said.
Often, even fire guards cannot stop the rush of flames as was the case in the Kelowna area this week. On Thursday, the blaze, which measured 130 square kilometres, jumped a fire guard near a residential area, starting a mass evacuation.
"In extreme cases, sparks can be blown kilometres away and there is no way they can construct fire guards that big," Mr. Feller said. Most fire guards are as wide as a couple of bulldozer blades at most -- fire fighters will use a bulldozer to remove organic material from a strip of land. They will also use rivers, lakes and roads to help them stop the blaze, but often they do little to help, he said.
By comparison, fires move slower than a hurricane, which brings winds of at least 117 km/h, or a swift-moving cheetah, which can go up to 112 km/h, but even at lower speeds, fires can be extremely violent and deadly.
According to federal government estimates, based on the area conditions and a scientific model forecasting what speed a fire might reach in any given area, fires in the region around Kelowna may have reached 3 km/h on Thursday, the last date figures were available. But experts close to the scene say the speed was far quicker.
All it takes is a bit of wind kicking up on a hill, especially a west or south facing one, to accelerate the speed, said Bill de Groot, fire scientist with Canadian Forest Service, which is part of Natural Resources Canada.
Even if the fires were as slow as under 5 km/h, they would be devastating. "If you are in the bush and you need to get out of the way of that, it is pretty fast," Mr. de Groot said.
HOW FAST CAN FOREST FIRE SPREAD: Maximum speeds compared:
Giant Tortoise: .27 km/h
Snake: 32 km/h
Human: 43 km/h
Fastest Fire: 50 km/h
Cheetah: 112 km/h
Hurricane: 117 km/h
The fastest human cannot outrun fire
The fastest human cannot outrun fire
'Sort of leapfrogs itself':
Flames can race through a forest at up to 50 km/h
Julie Smyth
National Post
Saturday, August 23, 2003
At their worst, forest fires can hit speeds approaching 50 km/h, moving faster than any human, as they rip down forests and ravage communities.
As emergency workers rushed door-to-door warning people of the escalating fires in and around Kelowna, B.C., where 10,000 people have been evacuated, residents feared strong winds would help fuel the blaze.
Fires need three things to pick up speed -- steep slopes, strong winds and a lot of dry, small fuel, such as pine needles or dead grass. The Okanagan area is full of open space, hills and pine trees, making it a perfect feeding ground for a raging fire. When fires get hot enough, they move up into the crown of trees -- any part where the bottom of branches reach --where there is a lot of oxygen, thousands of flammable needles and thin branches, all the components of a fast fire.
"You can probably get up to about 10 km/h, but fires can travel faster than that because what happens is this wall of flame shoots up a lot of burning embers and needles from the trees and they can be blown in front of the fire and set fire to another [tree]. It sort of leapfrogs itself, then it goes on and on. Then the speed can double or triple," Michael Feller, associate professor in forest sciences at the University of British Columbia, said yesterday.
The speed of a fire is difficult to measure but there have been reports of up to 50 km/h, he said.
Often, even fire guards cannot stop the rush of flames as was the case in the Kelowna area this week. On Thursday, the blaze, which measured 130 square kilometres, jumped a fire guard near a residential area, starting a mass evacuation.
"In extreme cases, sparks can be blown kilometres away and there is no way they can construct fire guards that big," Mr. Feller said. Most fire guards are as wide as a couple of bulldozer blades at most -- fire fighters will use a bulldozer to remove organic material from a strip of land. They will also use rivers, lakes and roads to help them stop the blaze, but often they do little to help, he said.
By comparison, fires move slower than a hurricane, which brings winds of at least 117 km/h, or a swift-moving cheetah, which can go up to 112 km/h, but even at lower speeds, fires can be extremely violent and deadly.
According to federal government estimates, based on the area conditions and a scientific model forecasting what speed a fire might reach in any given area, fires in the region around Kelowna may have reached 3 km/h on Thursday, the last date figures were available. But experts close to the scene say the speed was far quicker.
All it takes is a bit of wind kicking up on a hill, especially a west or south facing one, to accelerate the speed, said Bill de Groot, fire scientist with Canadian Forest Service, which is part of Natural Resources Canada.
Even if the fires were as slow as under 5 km/h, they would be devastating. "If you are in the bush and you need to get out of the way of that, it is pretty fast," Mr. de Groot said.
HOW FAST CAN FOREST FIRE SPREAD: Maximum speeds compared:
Giant Tortoise: .27 km/h
Snake: 32 km/h
Human: 43 km/h
Fastest Fire: 50 km/h
Cheetah: 112 km/h
Hurricane: 117 km/h
