The 19 Arizona firefighters killed Sunday while trying to protect the town of Yarnell were forced to deploy fire shelters to try and save their lives.
Arizona State Forestry Division officials said the firefighters' bodies were found amid 19 emergency shelters, with some of them inside the insulated tents and others outside. Their bodies were recovered Monday.
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Officials have pledged an extensive investigation to try and determine how and why the crew became trapped by the flames after an apparent shift in winds, and why the protective gear didn't seem to be effective or wasn't used by all the men.
Guidelines from the National Wildfire Coordinating Group recommend that the shelters be deployed on flat ground with little or no burnable material beneath them, and caution that it takes at least 15 to 20 seconds to get into one of the devices.
Experts say the timing is crucial. Getting under the shelter too soon allows heat to build up and oxygen to be depleted, but delaying too long can catch firefighters out in the open.
Those shelters are a giant, double-layered blanket with materials, including aluminum foil, that are used to shield a firefighter from both radiant heat and direct heat, while also allowing him or her to breathe relatively cool air rising from the ground.
Reporter Christopher Sign from our station in Phoenix traveled with a group of firefighters two years ago to learn more about how the shelters work and at what point they begin to fail.
The wildfire coordinating group says the shelters in use for the past decade can reflect up to 95 percent of radiant heat, the type that comes from the sun, and withstand direct heat from fire up to 500 degrees Fahrenheit.
Above that temperature, the glue that holds the shelter's protective layers together begins to melt and break down. If that happens while the flames endure, odds for survival plummet. Heat inside the shelter is capable of rising very quickly. Reporter Sign reported from his test that the inside can reach 200 degrees even in a shelter that's working properly.
Once removed from a case carried on a harness, a firefighter pulls the cocoon head-to-toe and with gloved hands holds the tent to the ground with straps as it's buffeted by winds and updrafts from the firewall. The key is creating a seal to keep smoke and ash out.
Emergency shelters have been required for wildland firefighters at the federal, state and local level since 1977, after the deaths of three firefighters without shelters during a fire in Colorado in 1976.
Since then, federal officials estimate the devices have saved more than 300 lives and prevented hundreds of serious injuries.
In a YouTube video, http://youtu.be/QJsY6foLh8o, posted by the NWCG, officials demonstrate how quickly these shelters can be deployed in an effort to save a firefighter's life.
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