The National Weather Service's Los Angeles page screams “Particularly Dangerous Situation (PDS)” in hot pink letters against a gray background.

It's a rare warning aimed at seizing attention ahead of extreme wildfire risk that's predicted to start in southern California at 4 a.m. Tuesday.

What You Need To Know

  • 'PDS' stands for 'Particularly Dangerous Situation'

  • A PDS Red Flag Warning goes into effect in southern California on Tuesday

  • It's a rare warning aimed at seizing attention ahead of extreme wildfire risk

PDS warnings were first used to warn of tornado outbreaks in the Midwest. More than a decade ago, three meteorologists proposed expanding their use to disasters such as ice storms, floods, hurricanes and now wildfires.

Grabbing attention

"It catches the attention, it really heightens that awareness and the need to really act at that point," said one of those scientists, Jonathan Howell.

The hope was that the phrase would “become synonymous with extreme weather events” and also could be used for emergencies such as hurricanes and snowstorms, Howell and two colleagues wrote for a presentation at a 2011 conference of the American Meteorological Society.

“I definitely think this has made an impact and has saved lives over the years," Howell, who is the science and operations officer at the weather service’s Mobile, Alabama office, told The Associated Press.

Past warnings

One of the earliest uses of the term “particularly dangerous situation” appeared in an April 1, 1983 Associated Press article about a widespread storm system that caused a blinding dust storm in west Texas. A tornado watch was posted for 24 counties in east Texas, with the National Weather Service warning: “This is a particularly dangerous situation with the possibility of very damaging tornadoes.”

In June 2005, the National Weather Service warned of a particularly dangerous situation as the environment was primed for a tornado outbreak over Oklahoma and Kansas.

The warning would be used to convey urgency in more tornado outbreaks in ensuing years. One was issued in November 2022 when supercells were expected across parts of Louisiana and Mississippi.

PDS warnings for wildfires

During the first week of November last year, as Santa Ana winds fueled the Mountain Fire northwest of Los Angeles, the National Weather Service issued a PDS warning. Forecasters called the threat “extreme and life-threatening.”

Then, on Dec. 9, residents of Los Angeles and Ventura counties were again warned of a “particularly dangerous situation” as Santa Ana winds roared through the mountains.

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