In the late 19th and early 20th centuries, signal flags were used to alert U.S. citizens to weather conditions. Postcard of the U.S. Weather Bureau Building at Charles City, Iowa. c. 1900.

The warning serves as a signal to officials and fire ... have additional local criteria for issuing red flag warnings based on the unique weather patterns and risks in their respective regions.

"It was a very visual, kind of pre-mass communications way to signal to people in the ... means that one has been sighted. Red flag warnings and fire weather watches can be for equally severe ...

The short take of a red flag flying signal is to stop. No burning leaves, bonfires and general caution should be used when the weather conditions favor fire danger.

Red flag warnings in Arizona signal an increased risk of wildfire ... according to the National Weather Service.Criteria for a red flag warning include a relative humidity less than 15%, warm ...

National Weather Service officials have upgraded an alert on fire conditions in a portion of the North Bay starting Sunday morning to a Red Flag Warning. The change signals increased confidence from ...

The National Weather Service issued a Red Flag Warning for Central Florida Thursday afternoon, including all east central counties, through 6 p.m. A Red Flag Warning is a signal that critical fire ...