USA — Imagine stuffing yourself into what’s basically an upside down sleeping bag made out of paper thin-cloth and aluminum foil, then lying down in front of the advancing wall of a raging wildfire.
Now stay there while the fire roars past, filling your fire shelter with choking smoke that makes your nose and eyes run as silver dollar-sized embers driven by strong winds rain down upon you.
The U.S. Forest Service estimates that 321 firefighters who did just that saved their lives and another 390 escaped being seriously burned.
But the shelters aren’t a fail-safe. Of 1,239 documented uses of fire shelters going back to 1977 when they became mandatory to carry, 41 firefighters have died in deployed or partially deployed shelters.
That’s why the U.S. Forest Service has just begun designing its third generation of fire shelters — led by a man who survived the deadly South Canyon fire on Storm King Mountain in Colorado two decades ago that claimed 14 lives, including nine Prineville Hotshots.
Toni Petrilli rode out the Colorado fire for 90 minutes in a fire shelter. So did seven other firefighters with him that day in early July 1994. Among those who died, four were in partially or fully-deployed shelters.
Petrilli is now the redesign project leader at the Forest Service’s Missoula Technology and Development Center.
In the wake of the June 2013 deaths of 19 members of the Granite Mountain Hotshhots in the Yarnell Fire of Arizona, the project was moved up a year, Petrilli said. Even so, the new shelter isn’t expected until 2018.
The initial steps include announcing to industry that the Forest Service is searching for new materials suitable for a fire shelter and talking to firefighters, Petrilli said. One of the key questions is “Do you feel like you take more risks because you carry a fire shelter?”
“We also ask them what do they want to see in a new fire shelter?” Petrilli said. “Do they want an all-protective shelter, do they want to lighter-weight shelter with similar performance in a similar weight and bulk. And if they want that all-protective shelter, how much weight are they willing to carry?”
A standard fire shelter is 86 inches long, 31 inches wide and stands 15 inches tall. It was released in 2003. Two years later, a larger shelter to accommodate bigger firefighters was created 96 inches long, 33 inches wide and 19.5 inches tall.
The shelters reflect radiant heat up to 500 degrees and trap breathable air close to the ground. Firefighters are trained to lie facedown and do their best to let the shelter’s aluminized, laminated fabric of Kevlar (used in bullet-proof vests) and the fire resistant cloth known as Nomex, not touch their clothing.
The goal of this redesign, the Forest Service Service says, is to improve the level of radiant and convective heat protection while maintaining the strength of the shelter.
For fire shelter survivors like Ryan Jordan, a U.S. Bureau of Land Management smokejumper who survived the Little Venus fire in the Shoshone National Forest in July 2006, training to use a shelter is nothing like actually doing it during a racing wildfire.
“You never think you’re going to have to do it,” Jordan said in a training video after the fire. “When you do it out on a lawn on a nice summer day, it’s easy to do. But in that situation the wind was blowing 50 to 60 mph — hard enough to pop trees over. Then you had the heat, the embers and the smoke.”
Petrilli remembers three pushes of heat, mostly smoke and embers, when he was in the shelter during the Colorado fire. He estimated the temperature inside at 110 degrees.
“There wasn’t a whole lot of direct flame coming into the area, but pretty good ember showers,” Petrilli recalled.
He and the other survivors on that ridge top were in an area previously burned over typically called “the black” by firefighters. That proved fortuitous.
As important as the shelter’s construction is where firefighters deploy it. Petrilli said that often means finding the biggest clearing nearby — if not in “the black,” a place where fuels are scant and the ground is even.
During the next 3 1/2 years, Petrilli said, firefighters will be interviewed about their fire shelter experiences. Different prototypes will be tested — on everything from carpeted meeting rooms to rock piles, roads and even behind the prop wash of an aircraft generating 50 mph winds.
Firefighting training also will continue to emphasize the most important aspect of fire shelters: Never being in a position to need them.
“Much more time is spent in training and on the fire line in entrapment avoidance,” Petrilli said. “The fire environment is very dynamic and the fire shelter is there just in case. It’s not meant to be a portable safety zone, it’s not meant to be a Superman suit.”