During a red-flag warning, residents are urged to avoid risky behavior like campfires or other open flames, smoking or setting off fireworks. The NWS also urges residents to have an evacuation plan, ...

During wildfire season, the National Weather Service has two advisories that inform people of dangerous conditions that could lead to blazes: a fire weather watch and a red flag warning.

Red flag warnings and fire weather watches for many parts of Oregon were set to continue July 30 and through July 31.

Smoke rises in the background as firefighters respond to a fire at the Flight 93 National Memorial headquarters, Oct. 3, 2014, in Shanksville, Pa. Daily American, Dylan Johnson/AP Photo ...

The two key ingredients for these warnings are wind and low humidity, although the thresholds vary depending on the region.