Updated

More than 100 large fires have swept across parts of the nation already this year, and the head of the U.S. Forest Service said Thursday the rest of the 2012 fire season is expected to be just as active as last year's, which saw historic wildfires on hundreds of square miles in Arizona, New Mexico, Texas and elsewhere.

Forest Service Chief Tom Tidwell said the Southwest continues to be dry, but the middle part of the U.S. up into the Great Basin could be in for a more severe season as drought marches across a bigger swath of the country.

"We need to understand the conditions that we're facing today. They're different than what we used to deal with," he told The Associated Press before a national conference call on the federal government's efforts to prepare for the season.

"These prolonged droughts, they affect the fire behavior that we see, and the more erratic weather that we're seeing, especially throughout the country this spring, those are the things we have to factor in," Tidwell said.

Federal scientists are monitoring weather patterns and trying to make accurate predictions so resources can be placed in the areas where they're needed most. And the Forest Service is working to add three more large air tankers to its fleet this year and 10 more next year.

"We take this responsibility very seriously. We know lives and property depend on it," U.S. Agriculture Secretary Tom Vilsack said during the conference call.

No state knows this better than Texas, where historic blazes last year destroyed more than 2,900 homes and burned nearly 4 million acres statewide. Wind-swept fireballs in the state were fueled by dry, dead grass and record-breaking heat.

Forecasters with the National Interagency Fire Center said the conditions are a little different this year. A lack of moisture in many places has resulted in fewer fine fuels on the ground, and the strong winds that pushed many of last year's fires are not expected to be as relentless. However, snowpack across the intermountain West left much to be desired, and the fuels that are out there are dry.

Vilsack said the West has a "full stock of hazardous fuels," partly because of damage done by bark beetles.

The western slopes of the Rockies are among the areas of concern this year, along with parts of Wisconsin, Minnesota and Hawaii and portions of the Southeast, officials said.

Still, forecasters at the fire center said the uncertainty in global weather patterns could lead to dramatically different outcomes for the 2012 fire season.

"Anything can happen," Vilsack said, noting the key to being prepared will be accurate predictions.

Add to the uncertainty the growing complexity of preventing and fighting fires in areas where homes and businesses are encroaching upon forests and other open lands.

Federal officials also stressed the importance of preventing human-caused fires and pushed the use of prescribed fires as a tool to better manage the nation's forests.

Fear of using fire to fight fire stems from incidents like a deadly wildfire last month in Colorado that started as a state prescribed burn. That blaze killed three people and damaged two dozen homes southwest of Denver.

"When we get into these droughty conditions, we have less opportunity to be able to use that as one of the tools, but it's just essential that we continue to address these hazardous fuels," Tidwell said.

Had it not been for prescribed fire and thinning efforts in southeastern Arizona over the past few years, the massive Wallow Fire could have been even worse, Tidwell said. He said the fire dropped out of the treetops and became more manageable in areas that had been treated.

While the U.S. Department of Agriculture's fire budget stands at more than $2 billion this year, Tidwell said residents need to do their part. The majority of fires across the country are caused by people, he said.

Tidwell spoke in Tijeras, a mountain community just east of Albuquerque. The mountainside behind him was covered by a dense grove of pinon and juniper trees with some 25,000 homes tucked here and there. He spent part of Thursday touring the area.

"If we can prevent just a few of those human-caused fires, it often will result in one less large fire from occurring," he said.

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Follow Susan Montoya Bryan on Twitter: http://www.twitter.com/susanmbryanNM

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Associated Press Writer Ramit Plushnick-Masti in Houston contributed to this report.