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Wildfires Out West - Enhanced Transcript

• Published: April 29th, 2011 in
• Originally broadcast on: on

Big Fires in the West

1. 0:03

   Nicole Heller: It probably won't come as a surprise that weather conditions and wildfires are related. That's because high temperatures leave the land thirsty and primed with dry wood that is easy to ignite

2. 0:16

   Nicole Heller: 2006 was one of the biggest fire years in recent history. You might remember the huge fires in Washington State and northern California. All together, more than seven million acres burned across the American West that year.

3. 0:30

   Nicole Heller: That's as much as Yellowstone, Yosemite, Rocky Mountain, Olympic and Death Valley National Parks combined. But hot, dry weather doesn't always lead to more wildfire. In some parts of the West big fires burn in wet years.

Wildfire and Climate

1. 0:46

   Nicole Heller: 2005 was a wet year, yet saw huge fires rage in Nevada. The reason? Nevada's desert landscape typically has too little vegetation to fuel wildfires. But when it rains, new plants grow and grasses fill in between the shrubs. Come summer, the extra plant growth provides enough fuel to spread a big fire. In contrast, the lush forests of Montana provide plenty of fuel for a fire to spread, but only when the trees have dried out enough to burn.

2. 1:23

   Nicole Heller: That's happening more often, as rising temperatures melt mountain snowpacks earlier in the spring. Rivers dry out earlier and forests get thirsty faster. The result is longer, more intense fire seasons.

3. 1:39

   Nicole Heller: In the last few decades, there were 17 times as many big fires in years with early snowmelt compared to years with late snowmelt.

4. 1:47

   Nicole Heller: Montana and Nevada show how different places respond in very different ways to the same conditions.

Studying Wildfires by Satellite

1. 1:57

   Nicole Heller: Scientists study these differences to help predict when and where fires will happen and how climate change will affect future fires. Images and data coming from NASA satellites are helping. They can pinpoint when and where fires are burning. They can also measure the "greenness" of the land — that is, how much photosynthesis is happening on the ground. Reds and browns mean the vegetation is sparse or dry, while greens show that plants are relatively abundant or moist.

2. 2:29

   Nicole Heller: Research shows that Montana's forests burn when the land looks red and brown. Nevada's scrub burns when the color is green.

3. 2:38

   Nicole Heller: In the future, as the climate warms, scientists expect to see less of that green. In the Southwest, which is already suffering from over a decade of drought, some lands may simply become too barren to burn.

4. 2:53

   Nicole Heller: But in the forested lands of the West, warming temperatures are likely to bring more big fire.