DENVER — Despite a wet spring over much of the nation, the Obama administration warned Tuesday of potentially catastrophic wildfires this summer, during a news conference meant to call attention to how federal funds are used to fight them.

As the summer heat dries out forests and rangeland, the fire danger will rise, said U.S. Forest Service chief Tom Tidwell, who joined Agriculture Secretary Tom Vilsack and Interior Secretary Sally Jewell at the Denver briefing.

Southern Arizona and drought-stricken California are especially vulnerable to large, costly fires, Tidwell said. Washington, Oregon, northern Idaho and western Montana will face increasing fire danger later in the summer, he said. Jewell said damage to homes and businesses, power grids and drinking water can cost millions and take decades to restore.

The Agriculture and Interior departments said federal firefighting costs are expected to range from $1.1 billion to $2.1 billion this year. The high end would exceed their combined firefighting budget of about $1.4 billion. If the costs exceed their firefighting budgets, the departments would have to transfer money from programs meant to reduce long-term fire danger by improving the health of forests and rangelands.

Vilsack, Jewell and Tidwell again asked Congress to allow the administration to take the cost of fighting the worst wildfires out of federal disaster funds, rather than their firefighting budgets, to protect long-term fire prevention programs.

The Obama administration says the worst 1 percent of all wildfires account for about 30 percent of federal firefighting costs.

“These are emergencies,” Jewell said. “They should be treated as such.”

She said the proposal has bipartisan support but the administration hasn’t been able to persuade Congress to act.

Vilsack added, “It’s not asking about new money. It’s about spending the existing resources a different way.”

The House Appropriations Committee on Tuesday proposed a budget of $3.6 billion for both wildland firefighting and prevention for the fiscal year that starts in October, $52 million more than the current budget, committee spokeswoman Jennifer Hing said.

The measure doesn’t change the way major fires are paid for, which brought criticism from Tidwell.

“We’re disappointed that we didn’t have the committee understanding precisely what’s at play here,” he said.

Hing said changing the way wildfires are paid for would require Congress to revise laws that govern the budget process and disaster recovery spending.

Rep. Rob Bishop, chairman of the House Natural Resources Committee, said funding isn’t the answer to the worsening wildfire problem.

“Throwing more money at it, without changing management practices, does not cut it,” said Bishop, a Utah Republican. “The Forest Service must start thinking creatively. There must be a change in the mindset and a change in their management.”