Every National Forest in California will be temporarily closed to the public due to the ongoing threat from wildfires burning across the state.

The state’s 18 national forest areas will be closed as of 11:59pm Tuesday, and remain closed at least until September 17. In a statement, the U.S. Forest Service said the move was made “to better provide public and firefighter safety due to the ongoing California wildfire crisis.” That includes a devastating fire that has forced thousands of people to evacuate Lake Tahoe as the flames encroach.

This comes ahead of the Labor Day extended weekend, when many families would likely consider visiting a scenic destination such as the Sequoia or San Bernardino National Forests. But unusually dry conditions have stretched firefighting resources to the limit. Weather conditions haven’t helped, either.

The Forest Service cited it as one of several reasons behind the decision to shut the forests:

 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.

A word of warning: Anyone caught illegally entering Forest Service lands — which includes developed campgrounds, hiking trails and recreation sites — typically can face fines of up to $5,000 for violating closure orders.

The closure order only applies to Forest Service lands. State and national parks and private lands set their own rules.