The cost of fighting wildfires in Oregon skyrocketed to $454 million in 2017, the most so far this century, according to data from Northwest Interagency Coordination Center.

The high cost was fueled by multiple large wildfires — and more than 2,000 total fires — that burned 665,000 acres statewide.

Between 2010 and 2015, federal and state agencies spent an average of $146 million on Oregon wildfires. That number more than tripled in 2017.

“The 2017 fire season was particularly long and arduous in the Pacific Northwest,” U.S. Forest Service spokesman Stephen Baker said. “Many of the large fires this year were long-duration fires that required a vast number of resources, in some cases from mid-July through September and even October.”

The number of acres burned in 2017 wasn't a record, or even particularly close. In 2012, more than 1.2 million acres were blackened, but most of it was in southeast Oregon grassland.

The major fires of 2017, however, burned primarily in forestland often close to homes and infrastructure, driving up cost, officials said.

Two of Oregon's largest fires, Chetco Bar and Eagle Creek, were declared the nation's top priority during late August and September. Both fires were managed by fire crews that reached 1,500 people and required deployment of the Oregon National Guard.

“At one point, we had more than 10,300 firefighting resources assigned in the Pacific Northwest,” Baker said. “Many of the regional air tanker bases also had record-breaking seasons.”

Photos: Eagle Creek Fire

The reason for the heavy wildfire season was multifaceted, said Kari Cobb, spokeswoman for the National Interagency Fire Center.

The previous winter brought above-average precipitation and snowpack, which led to the growth of extra fuels, she said. But those fuels quickly dried out with above-average and often scorching temperatures in early summer, “which becomes really combustible,” Cobb said.

Add two major lightning storms to the mix, as occurred statewide in June and July, and you had a recipe for trouble, Cobb said.

“There was a lot of fuel, and it dried out quicker than it normally would,” she said. “That's often going to lead to a bad wildfire season.”

Cost of fire suppression in Oregon

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Cost of fire suppression in Oregon

2017: $454 million

2016: $53 million

2015: $218 million

2014: $269 million

2013: $183 million

2012: $102 million

2011: N/A

2010: $50 million

Source: Northwest Interagency Coordination Center

Acres burned by wildfires in Oregon

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Acres burned in Oregon

2017: 664,824 acres

2016: 219,509

2015: 685,809

2014: 984,629

2013: 350,786

2012: 1,256,049

2011: 285,712

2010: 93,731

2009: 100,668

2008: 136,572

2007: 648,046

2006: 545,870

2005: 155,331

2004: 30,018

2003: 160,191

2002: 1,010,952

Source: National Interagency Fire Center

Zach Urness has been an outdoors writer, photographer and videographer in Oregon for 10 years. He is the author of the book “Hiking Southern Oregon” and can be reached at zurness@StatesmanJournal.com or (503) 399-6801. Find him on Twitter at @ZachsORoutdoors.