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viernes, 15 de febrero de 2008

Articulo Kirk Johnson. www.nytimes.com. 15/12/07

Kirk Johnson


Nobody on Michael E. Hutt’s team has illusions that wildfire can be tamed. The blazes in Southern California in October were lesson enough for that.

“When a 60-mile-an-hour Santa Ana is blowing, there’s not much anybody can do,” said Mr. Hutt, a scientist with the United States Geological Survey.

Foto: www.nytimes.com

But if the stakes are huge in Western wildfires, so too are the tools that researchers like Mr. Hutt are newly bringing to bear. He and his team are studying Grand County, a corner of Colorado 90 minutes west of Denver, with what Mr. Hutt described as a giant machine for playing what if.

A one-of-a-kind computer modeling project, its mission is to give land managers, community leaders and the public a way to analyze fire risk and assess options as never before.

What if a fire breaks on a particular slope? How many homes are within one mile? What will be the expected chemical signature of the ash and the smoke, and the likelihood and projected impact of fire debris reaching an important water source in the next 48 hours? What evacuation routes should be chosen, or ruled out, based on the predictions of the fire’s movement, the weather and other variables?

The United States Forest Service is supplying data on soil moisture. The Civil Air Patrol, the civilian air-rescue arm of the Air Force, is sending images from its training flights. Ash from the fires in California is being analyzed in Colorado and will be used to help project Grand County’s expected ash composition from fire.

The researchers say that if ever there was a place to see what fire science can achieve before a fire actually erupts, Grand County is the candidate. The population and number of second homes are growing rapidly, and the forest that tucks in around the new homes is dying, attacked by beetles that are killing lodgepole pines in numbers that scientists say they have never seen.

About three million people in the Denver metropolitan area draw at least part of their water supply from the county’s reservoirs, and millions more depend on the Colorado River, which has its headwaters a few miles away in Rocky Mountain National Park.

Lodgepole-dominated forests, even when they are healthy, burn furiously, but rarely, with ground-clearing fires that happen only every few hundred years. The lodgepoles here are overdue. A big fire in 1851 scorched part of the area, but some places have not burned for 500 years or more.

“We have the full spectrum here,” said Kelly Elder, a hydrologist and scientist-in-charge at the United States Forest Service’s Fraser Experimental Forest. The beetles (which may be worsening because milder winters are not killing them off), a surging population and a warming climate are all connected, Dr. Elder said. “This is a mature forest that’s ready to burn.”

Building computer models is complex, scientists say, and there is not a lot of federal money to do it. Federal firefighting budgets have been stressed by recent major fires, scientists say, but a national expansion of the Grand County project could help decision makers set priorities. If 20 fires happened to be burning in several states, a modeling system could rank those fires according to criteria like the drift of the smoke and the potential impact on homes, businesses, water and wildlife. How many people and how much landscape might be affected by each fire, by each criterion, and at what cost?

“Every time we have a fire we learn more about how these systems respond,” said Deborah Martin, a hydrologist with the United States Geological Survey who is studying ash from the California fires.

Wildfires this year have burned more than 8.9 million acres, including more than a million in California and almost two million in Idaho, federal figures show, making 2007 the second-highest year for total acres burned since the current system of measurement began in 1960.

Records have been broken every year since 2004. “We’re having more fires more often, burning with a lot more severity than before, with more people living close,” Mr. Hutt, the associate director of the Rocky Mountain Geographic Science Center at the geological survey. “We can’t change those things, but we can be smarter.”

Another important goal at a time when millions of Americans are building homes close to national parks and forests is to open the modeling system to the public. Experts say decisions like clearing trees from property or installing metal roofs are often the first and best lines of defense.

Some researchers, however, question what the models will really achieve. Pressure to fight every fire endangering every house on the edge of every forest will continue to be intense, they say, no matter how sophisticated the analysis.

“I think the role that science can play is limited,” said Jacqueline Vaughn, a professor of political science at Northern Arizona University who teaches environmental policy. Professor Vaughn recently visited burned areas in California and concluded that community response and self-defense measures had been crucial and had varied widely.

“Some people get it, and some people just don’t,” she said.

Fire planning can also have consequences. Officials at the Northern Colorado Water Conservancy District have been trying to take a proactive role in protecting their water supply for Grand County cities like Greeley and Fort Collins.

If ash posed a threat, for example, debris dams might be installed in streambeds to halt the flow of ash before it could hit the reservoirs. The plan, however, was rejected by the National Park Service and the Forest Service “because it would have too big an impact and limit fish migration,” said Jeff Drager, deputy manager of the engineering division for the water district.

The fallback position, Mr. Drager said, is to have material for the dams at the ready and to build them on the fly as needed.

“That’s probably our most promising hope right now,” he said. “That, and cross our fingers.”

Fuente: www.nytimes.com
Fecha: 15/12/07

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