Visualizing the wildfires in Washington and Oregon, in maps and satellite imagery

The American West is battling a persistent wildfire season, with the Pacific Northwest bearing the brunt as dozens of massive blazes rage in Oregon and Washington, forcing residents from their homes and shutting down major roadways.

At least 29,000 firefighters were battling more than 100 uncontained large fires nationwide on Monday, according to the National Interagency Fire Center. Seven new blazes erupted on Sunday alone, adding to the strain.

This year's fire season is shaping up to be quite destructive. Wildfires have already scorched more than 5.1 million acres across the country - at least a million acres more than the 10-year average for this time of year, the agency said.

With nearly half of the nation's active large fires concentrated in Oregon and Washington, CNN is tracking the latest in maps, charts and satellite imagery.

Three major wildfires are burning near Spokane, Washington.

The fires in the Pacific Northwest have blanketed the region with smoke, pushing the air quality index to unhealthy levels across Washington, especially for residents who are sensitive to particulate pollution.

More than 30 cities in the region had air quality readings in the very unhealthy or unhealthy range as of Monday afternoon, according to AirNow.gov.

Aerial images captured by Nearmap show the Old Trails Fire sweeping through neighborhoods in Spokane County on Saturday afternoon. Captured around seven hours after the fire began, they show hundreds of burned homes and firefighters trying to halt the spread of the blaze.

Officials have said more than 700 buildings were destroyed. The photos, which were taken during the blaze, do not capture the full scale of the destruction.