By Scott Hammers • The Bulletin

The past month has been one of the smokiest in Oregon history, but in terms of how much Oregon forest has burned, 2017 is far from being the state’s worst fire season.

So far this year, “large fires” — more than 100 acres of timber or more than 300 acres of grassland — have burned just over 640,000 acres across the state, according to figures collected by the Northwest Interagency Coordination Center, a Portland-based group that coordinates wildfire incidents for 11 firefighting agencies in Oregon and Washington.

The number is likely to continue climbing. Many fires still burning will consume more acreage before they are extinguished, but in some cases, acreage estimates are downgraded as firefighters get a handle on the fire and the extent of the damage can be more accurately mapped.

In 2014, nearly 1 million acres burned in Oregon, including the 6,908-acre Two Bulls Fire just west of Bend, and the nearly 400,000-acre Buzzard Complex range fire in the state’s southeast corner.

In 2012, another massive range fire in southeast ­Oregon, the Long Draw Fire, torched 558,000 acres, helping boost the total acreage burned in the state to a 1.3 million acres.

There have been slow fire years in the recent past as well. In 2009 and 2010, the total acres burned across the state remained below 100,000.

Because wildfires most often burn well away from populated areas, and because most people seldom think in terms of tens or hundreds of thousands of acres, it can be difficult to grasp how large any given fire really is.

One square mile is the equivalent of 640 acres. Smith Rock State Park, at 641 acres, provides a familiar measure of how large a 1-square-mile fire is.

Redmond’s city limits encircle 16.8 square miles, or 10,752 acres. Sunriver covers approximately 3,300 acres, while the in-bounds skiable area at Mt. Bachelor totals 4,318 acres.

At 33.3 square miles, or 21,312 acres, the city of Bend is about two Smith Rock State Parks shy of the area burned this summer by the Milli Fire west of Sisters.

Taken all together, the nearly 700,000 acres burned in Oregon this year would cover just more than one-third of Deschutes County’s 1,955,000 acres, or just about 1 percent of the total land area in the state.

Oregon’s biggest fire this year, the Chetco Bar Fire near Brookings, has burned almost 180,000 acres so far, the equivalent of almost nine Bends. The Eagle Creek Fire in the Columbia River Gorge has burned an equivalent of roughly three Redmonds.

Carol Connolly, public information officer with the Northwest Interagency Coordination Center, said acres burned is one of many ways to measure the severity of a fire season.

Connolly said there’s a lot of random chance in how many acres burn each fire season. Lightning and where it strikes is the biggest factor, she said. Due to a return to more typical weather patterns, this summer has been the first fire season in about five years with more lightning-caused fires than human-caused fires, she said.

Often, it’s one or two huge fires that drive the acreage totals in any given year, frequently fast-moving fires in grassy rangeland on the eastern side of the state.

Past wildfires have been considerably more massive than anything Oregon has seen so far in 2017.

The Biscuit Fire of 2002 burned almost 500,000 acres in Southern Oregon and Northern California, the biggest forest fire in the state’s recent past. The biggest fire in state history, the Silverton Fire of 1865, burned an estimated 990,000 acres southeast of Salem.

The region’s largest-ever fire, the “Big Burn” of 1910, blackened more than 3 million acres across Washington, ­Idaho and Montana, but even that is small compared to the biggest fires on record — a series of wildfires on the ­Indonesian islands of Sumatra and Borneo in 1997 and 1998 burned an estimated 24 million acres, an area more than one-third the size of Oregon.

— Reporter: 541-383-0387,