Wildfire squasher: meet a scientist who fights fire with fire.

A flame ignites a tree. The blaze grows and travels up a slope, setting more trees on fire. Kara Yedinak stands nearby and observes, wondering which way the flames will go next. This 26-year-old is more than just a daring onlooker. As a physical-science technician at the Fire Sciences Lab in Missoula, Montana, Yedinak leads a team that performs carefully staged burn experiments to study the behavior of fire. "I look at flames to learn why they do what they do," she says.

Most of Yedinak's scorching research takes place inside a lab where safety measures are strictly enforced. Her experiments in burning fake "trees" indoors help scientists at the lab predict how wildfire spreads under various circumstances. That knowledge could help firefighters to more effectively battle real-life fires in the wild.

MAPPING FIRES

Yedinak's experiments often focus on two important factors that cause a wildfire to spread: the speed and direction of the winds that are fanning the flames and the slope of the terrain across which the fire is spreading. "One way fire transfers energy is through convection, or direct contact of heat. Wind and slope affect convection," Yedinak explains.

For example, when a wind blows across a flame, it causes the flame to tilt. If the flame points up a slope, the trees standing uphill of the flame become easy targets for catching on fire. "The wind pushes all the hot gases into the next set of [trees] that has not burned yet," says Yedinak.

To learn how flames spread under different conditions, Yedinak sets up vertical fuel rods--which represent trees--on a platform in the lab. Then she ignites the trees from one side and observes how the fire grows. Using sensors, she collects data such as the size and the temperature of the flames, and how fast the flames move. For each of her hundreds of burn experiments, Yedinak adjusts variables such as the height of the trees, the slope of the platform on which the trees are attached, and the speed of the wind tunnel that blows on the flames.

Her data are eventually used to build computer models of different wildfire-prone regions. These models help scientists predict how a wildfire in a specific terrain would spread under certain given conditions. This information could help the area's fire chief devise effective strategies for fighting wildfires.

FIRE STARTER

Yedinak, who grew up in Ennis, Montana, didn't plan on becoming a fire scientist. But at an early age, she knew that she liked science. When her third-grade teacher brought a cow eyeball into school for the class to dissect, "many people screamed," she says. "But I thought that it was the coolest thing."

During high school, Yedinak became particularly interested in physics. But some of her teachers discouraged her from pursuing the subject. "I had a bit of trouble with math, which is an important part of physics," she says. "But I loved physics. So I worked really hard." The hard work paid off: Yedinak received a degree in physics from Pacific University in Oregon. Uncertain of which career path to take after graduation, Yedinak worked in an internship that led her to her current job at the fire lab. "I just fell in love with the science," she says.

Did You Know?

* The burn chamber at the Fire Sciences Lab has a 30 meter (100 foot)-tall ceiling. "We are able to do some pretty spectacular burn experiments in there," says Kara Yedinak.

* A blaze does not have one constant temperature. "It's a wild mosaic of different temperatures," says Yedinak. So during burn experiments, she uses highly sensitive sensors to measure the temperatures at different parts of a flame.

* Yedinak is trying to find ways to help fight crown fires. These wildfires travel very quickly through the tops of trees. "They are pretty intense and very hard to control," says Yedinak. "It's very dangerous to be around them."

RELATED ARTICLE: Mickey Mclain.

FUTURE FIREFIGHTER

Seventeen-year-old Mickey can't wait to become a professional firefighter. Most areas in the U.S. require a person to be at least 18 years old before applying for training. But the teen from Edmonds, Washington, is getting a head start in her studies. In the summer of 2005, Mickey attended Camp Blaze, a firefighting camp for young women between the ages of 16 and 19. For one week, Mickey and camp participants from across the country lived in a fire-training center in North Bend, Washington. There, they attended classes taught by female firefighting professionals. Mickey learned about protective equipment and practiced skills such as search and rescue. She also got hands-on training in putting out flames. "They set these cars on fire, and we had to work together to put them out." One key lesson Mickey learned about firefighting: "It's about teamwork. If you're not paying attention, you could hurt the others you're working with." Learn more about Camp Blaze at: www.campblaze.com.

RESOURCES

* For information on the various wildfire-fighting jobs with the National Park Service, visit: www.nps.gov/fire/developmental /developmentalopportunities.cfm

* Learn more about wildfires with the interactive activities found at this Web site: www.firewise.org/fw_youcanuse/index.htm

* For a trove of information about wildfires, visit the site of the National Interagency Fire Center: www.nifc.gov

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For more information about the Fire Sciences Lab, visit: www.firelab.org