This is the official blog for Bryan Norcross, Hurricane Specialist at The Weather Channel.
By: Bryan Norcross , 02:58 GMT le 04 septembre 2012
Another hurricane, another mangled message. Let's see. All of the affected coastline and, explicitly, Lake Ponchartrain went under a Hurricane Warning Sunday afternoon, August 26. All of the affected coastline was in the cone. At 4 AM CT on Monday a storm surge forecast of 6 to 12 feet was issued for Southeast Louisiana, Mississippi, and Alabama. Isaac made its first landfall at 6:45 PM CT on Tuesday at the southern tip of Plaquemines Parish.
There was plenty of time for action.
We knew for a week that Isaac's huge circulation was going to move a lot of water, no matter its category or highest wind. The trajectory of the wind aimed that water right at Louisiana's southeast coast and wouldn't let up. Plaquemines Parish has plans to build up the "back levee", but Isaac tragically showed that plans don't hold back the water. The relentless onshore flow pushed the Gulf high enough to top the 8 1/2 foot levee, and a horrendous experience ensued for people that stayed home, thinking whatever they were thinking, but coming to the conclusion that the levee was high enough.
So why would people stay behind an 8 1/2 foot levee when the forecast was for 6 to 12 feet of water and waves on top of that? And why would people in LaPlace to the west of New Orleans or Slidell to the north be surprised they got flooded when there's no real levee at all protecting them?
Questions have been asked and the research is being compiled from the affected coastline to try to understand what people thought was going to happen and when they thought it. What and who were their credible sources of information? What words or messages would have made a difference? How can we do better next time?
I'm sure the research will be wonderful, but we pretty much know what happened. People heard on the media, "it's only a Tropical Storm", "it might not even make Category 1", "the models are all over the place", "there's tremendous uncertainty", "it's no Katrina", blah blah blah.
The message for Plaquemines Parish should have been, "Listen, if the forecast is right, the Gulf is coming over that levee and the water will be up to your roof. Now get the hell out!"
Everybody's a meteorologist today, they look at the models, slice and dice the uncertainty, and the message from the National Hurricane Center gets mangled beyond recognition. In fact, for the two days before the first landfall and for the tortuous days thereafter, the forecast was plenty good. The storm stayed well within the cone. The hurricane hit in the Hurricane Warning area, and, more importantly, didn't hit outside the warned zone.
The NHC's system for disseminating the forecast is archaic and relies on the media to sort it out and get it right, but the content was all there.
In the Hurricane Center advisory, the critical storm surge forecast was buried toward the bottom of the text. In newspaper terms, that's like putting the main headline in the sports section. The discussion of the scope of the impact of the storm related to its large size was relegated to the somewhat technical "Discussion". And more key pieces of information are scattered hither and yon.
It's up to the media to assemble a precise, informed, and consistent message from the torrent of good information that comes out of the National Hurricane Center. It's hard for us at The Weather Channel to digest it all at advisory time, and we've got more meteorologists that you can shake a stick at. Four of us on the Tropical Team were working on it Tuesday evening at landfall, and it was still hard. And nobody else has close to our resources.
And then there's the local National Weather Service offices. They, too, make excellent forecasts, but their communications systems seem doubly determined to make it difficult to find out what they are forecasting. The bottom line, if it takes more than one click to find critical information for Tampa or Mobile or Slidell or anywhere else, the system is broken.
The good news is, there is awareness within the National Weather Service that communications is not their strong suit. There are plans for explicit Storm Surge Warnings and other improvements as well. And, there are excellent people working on the problem. Let's hope Isaac sends a message to Washington that it's time for action.
And... the media has to man up. All of it. Everybody. Hurricane Warnings, storm-surge forecasts, the ability of large circulations to move a lot of water, the entire discussion has to be had over and over in a situation like this. No quick hits, no hitting high points, and no trivializing chatter about the models.
The standard for ALL media should be how well their viewers or readers understand the message. If a big percentage of the people who get their information from you end up misinformed, you suck as a news outlet. That used to be the standard, and should be the standard again. Do people get the message and understand what it means to them? That's the only question that counts. End of story.
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