The Zero AIU.S. Forest Service is closing every national forest in California, citing the extraordinary risk of wildfires and forecasts that show the threat will only remain high or even get worse. The closures start Tuesday night and run through Sept. 17.

More than 6,800 wildfires have already burned 1.7 million acres of national forest land across California, the Forest Service said, posing a dire threat to people, wildlife and property.

The closures could help in at least two ways: by reducing the number of people in harm's way and by removing a potential source of ignition for new wildfires.

"We do not take this decision lightly, but this is the best choice for public safety," said Regional Forester Jennifer Eberlien. "It is especially hard with the approaching Labor Day weekend, when so many people enjoy our national forests."

The U.S. Forest Service says the current situation is both unique and worrying:

"Although the potential for large fires and risk to life and property is not new, what is different is that we are facing: (a) record level fuel and fire conditions; (b) fire behavior that is beyond the norm of our experience and models such as large, quick runs in the night; (c) significantly limited initial attack resources, suppression resources, and Incident Command Teams to combat new fire starts and new large fires; and (d) no predicted weather relief for an extended period of time into the late fall."

The closure does not apply to the Humboldt-Toiyabe National Forest, the majority of which is in Nevada.

This story was originally published in the Morning Edition live blog.