‘PDS’ warnings were made to grab attention in tornadoes, hurricanes, and now wildfires

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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. (1200GMT) Tuesday.

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.

“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,” said Howell, who is the science and operations officer at the weather service’s Mobile, Alabama office.

The weather service’s Storm Prediction Center — whose mission is to provide “forecasts and watches for severe thunderstorms and tornadoes” — says that the term was first used on April 2, 1982 by forecaster Robert H. Johns, in conjunction with a tornado watch.

That came after a “failed attempt in the late 1970s,” Johns said in an interview in the Electronic Journal of Severe Storms Meteorology. Meteorologists had alerted the public to a “big next day,” only to see no severe weather, he said.

Today, meteorologists have better tools to predict catastrophic weather outbreaks than they had in the 1970s and 1980s and forecasters can more reliably issue severe warnings, Howell said.

The PDS term appeared in newspaper articles such as an April, 1, 1983 Associated Press story about a widespread storm system that caused a blinding dust storm in West Texas.

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.