-- — The National Weather Service's warning in New Orleans the morning before Hurricane Katrina hit in 2005 still stands out as one of the agency's most urgent alerts ever issued.
The massive storm had strengthened to a Category 5 with sustained winds of 175 mph the night of Aug. 27-28, prompting the Weather Service to predict "a most powerful hurricane with unprecedented strength." The prediction noted that "most of the area will be uninhabitable for weeks, perhaps longer" and that "persons, pets and livestock exposed to the winds will face certain death if struck."
The warnings have been credited with getting thousands to move out of harm's way in Mississippi and Louisiana, although the focus on wind damage was largely misplaced. It was coastal storm surge and flooding from breached levees that killed an estimated 2,000 Gulf residents and caused more than $100 billion in damage.
Almost exactly six years later, the last alert for Hurricane Irene before its first U.S. landfall -- in North Carolina on Aug. 27 -- warned of "extremely dangerous storm surge" as high as 11 feet in North Carolina and 3 to 6 feet along the New Jersey shore, plus "large, destructive and life-threatening waves." The advisory predicted rainfall of 6 to 10 inches and isolated maximums of 15 inches from North Carolina to New England.
Perhaps the most succinct storm advice came from New Jersey Gov. Chris Christie: "Get the hell off the beach." Hundreds of thousands did so, although many stayed put.
While those who ignore public safety requests during storms rarely face sanctions, a newly enacted Oklahoma law allows police to impose fines on those who drive around barricades into a flooded road. Penalties can equal the cost of any rescue effort to pull people from harm -- plus the typical $1,000 fine or 30 days of jail time for going around any road barrier.
As hurricane season hits its peak, the Weather Service has launched a new campaign to make more precise and relevant forecasts. It's working with community leaders and emergency managers to make the public more receptive and more "weather-ready."
"Unfortunately, there's no one approach that will get people to pay attention to warnings and understand what they mean," said Jay Baker, a Florida State University geography professor who studies disaster-alert responses. "A lot depends on the hazard and how they perceive the threat personally."
While some argue that officials over-evacuated for Irene and made it less likely the public will respond to future alerts, Baker's research has found that people still pay attention even after several storm warnings in a season, whether for hurricanes, tornadoes or other threats.
"The greater hazard comes when you have warnings for things that most people have no experience with. A lot more people think they've been through the worst of a hurricane, when actually they've only been at the edges," Baker added.
With nearly 50 deaths from Irene and more than 500 fatalities from tornado outbreaks so far this year, authorities are again looking at how warnings are given and perceived.
Besides plainer language, some of the program's experiments include putting forecasters inside emergency-management centers at key periods, seeking more help from social scientists on preparing advisories and tapping social-media outlets to spread warnings.
Harold Brooks, a research meteorologist at the National Severe Storms Laboratory in Norman, Okla., noted that deaths from tornadoes have leveled off in the past 15 years after steadily declining since the 1920s.
In Joplin, Mo., a May 22 tornado killed at least 152 people, according to the Missouri Emergency Management Agency. Many of them were found in overturned cars and trucks or in the rubble of collapsed stores, suggesting they didn't hear or perhaps didn't understand a warning issued 30 minutes before the twister struck. The area had been under a tornado watch for four hours.
Scientists are trying to figure out how many people don't hear sirens and broadcasts because they're listening to music or movies or otherwise distracted, and how many don't understand how imminent a threat may be.
"Protecting life and property is not as simple as issuing a forecast," said Jack Hayes, Weather Service director, about a 2009 report on responses to tornado warnings during the February 2008 "Super Tuesday" outbreak. "A number of barriers often deter people from making risk-averse decisions."
The review, which included hundreds of survivor interviews, found that more than half of the victims didn't have access to a safe shelter. Some minimized the threat because it was wintertime; many others displayed "optimism bias" -- the belief that bad things only happen to others. Quite a few sought protection only after they saw a tornado bearing down.
"It apparently takes visual images to make some people react," said Kevin Knupp, head of a research team at the University of Alabama in Huntsville that's studying warnings and reactions in connection with that state's April storms. "... If we need pictures of an approaching tornado to make people take shelter, then we've got a problem."
Baker said many people either don't appreciate the power of nature or seem to comprehend their location in an affected area.
"One of the complaints has been that countywide warnings are too vague," he said. "I hear and read tornado warnings that tick off a list of town names and times that are in the expected path, yet if people are not familiar with those particular spots in their community, this does them no good."
Baker has seen phone surveys from barrier-island communities where 30 percent of residents didn't think they were at risk from a hurricane. "And I worry that the people who agree to answer the surveys may be better informed than the population as a whole."