As 26 major wildfires currently rage across the American West – 18 of them in Oregon and Washington – they’re rapidly burning through firefighting budgets as well.

As a result, experts warn, firefighting agencies such as the US Forest Service and the US Department of the Interior have to raid other fire-related programs – forest management and fire preparedness, for example – to battle the blazes.

The reasons for this are multiple and complicated: Years of fire suppression instead of letting fires burn naturally allowed fuel levels to grow dangerously; climate change has brought on changes in weather patterns; and housing and other development pushed into what’s known as the “wildland-urban interface” – some 60 percent of all new homes built since 1990, according to environmental economist Ray Rasker.

“Changing climate is a dominant driver,” says Jason Funk, senior climate scientist for the Union of Concerned Scientists (UCS), noting in a conference call with reporters Wednesday that the typical fire season has grown from five months to seven months.

For one thing, changing climate has meant smaller snowpacks. That makes for more dry fuel, as well as stressed trees vulnerable to disease and insect damage. For example, the acreage damaged by bark beetle infestations around the West and therefore less fire resistant amounts to an area about the size of Colorado.

“Effectively, we have a tinderbox the size of Colorado just waiting for a spark,” Dr. Funk says.

“The amount and intensity of forest fires tends to increase every year,” agrees Jim Douglas, director of the Interior Department’s Office of Wildland Fire. “This year, we expect to spend as much as $1.8 billion – nearly $500 million more than available to the Forest Service [part of the Agriculture Department] and the Interior Department.”

A new UCS report, “Playing With Fire,” makes a direct connection between wildfires and climate patterns.

Since 1970, temperatures in the American West – much of which is experiencing drought today – have increased by about twice the global average, according to the report. As the length of the fire season has grown since the ’70s, the annual number of large wildfires has increased by more than 75 percent.

“In the last 10 years, the acres burned per fire doubled and the average fire burned twice as long,” writes Dr. Rasker, executive director of Headwaters Economics, in a Denver Post op-ed column. “Since 2010, the number of structures destroyed tripled and firefighter fatalities rose fourfold.”

Meanwhile, the expense of fighting wildfires and protecting life and property from harm is nearly four times greater than it was 30 years ago and has exceeded $1 billion every year since 2000 (in 2012 dollars). The share of the Forest Service budget devoted to fire management rose from 13 percent in 1991 to more than 40 percent in 2012.

“It’s very clear that these fires are getting bigger, they’re getting hotter, and they’re getting more damaging,” US Sen. Ron Wyden (D) of Oregon said on the UCS conference call Wednesday. “Our fire season actually began this winter.”

Sens. Wyden and Michael Crapo (R) of Idaho are sponsoring bipartisan legislation that would move fire suppression funding out of the Forest Service and Interior budgets into an emergency disaster fund to prevent the siphoning of cash from other programs.

In essence, the bill provides that major wildfires be treated like hurricanes and earthquakes for purposes of federal funding.

“This is about as common-sense as it gets,” Wyden said in introducing the bill. “Congress needs to fund the biggest, most catastrophic wildfires like the natural disasters they are, and free up funding to break the destructive cycle that underfunds fire prevention and shorts fire management.”

At present, the Carlton Complex fire northeast of Seattle stands at 250,136 acres and is 16 percent contained. Rain and cooler temperatures are helping firefighters battle the largest blaze in Washington State history, which has destroyed 150 homes so far.

On Wednesday, President Obama signed an emergency declaration authorizing the Federal Emergency Management Agency and the Department of Homeland Security to coordinate disaster relief and help Washington State and local agencies with equipment and resources.

Mr. Obama also has asked for $615 million in supplemental funding for firefighting this year.

According to the National Interagency Fire Center in Boise, Idaho, the current fire season looks like this:

“Above normal fire potential will persist over much of California, the Northwest, and the Great Basin in July. In August, above normal fire potential will continue over most of California, Nevada, Oregon, Washington, and Idaho.”