Weather

New National Weather Service maps will focus on flood risk in hurricanes

BY JEFF ADELSON| JADELSON@THEADVOCATE.COM

Hypothetical example of the new storm surge potential map that will be issued by the National Weather Service when hurricanes or tropical storms threaten to make landfall.
Hypothetical example of the new storm surge potential map that will be issued by the National Weather Service when hurricanes or tropical storms threaten to make landfall. Advocate graphic, modified from map provided by the National Weather Service

Forecasters and emergency preparedness officials have struggled for years with a potentially life-threatening issue when it comes to warning people about the dangers of an approaching hurricane.

The problem is that the simplest and most commonly used way of describing a hurricane, the well-known category system based on wind speed, gives little indication of how badly its storm surge will flood coastal areas.

That issue was demonstrated dramatically in 2012, when the relatively minor Hurricane Isaac caused massive and widespread flooding.

This year, the National Weather Service is trying to tackle the problem by redirecting the focus from wind speed to storm surge.

Storms still will be referred to by the Saffir-Simpson Hurricane Wind Scale, which ranges from low-intensity Category 1 to devastating Category 5. But forecasters now also will release detailed maps showing how severe the flooding could be when the storm comes ashore — at least outside the levee system that surrounds much of Orleans, Jefferson and St. Bernard parishes.

Inside that protective system, residents will be warned about the possibility of flooding but without the level of detail available in outlying areas.

The new modeling, combined with earlier and broader analyses that will be shared with local officials as they decide whether to call for evacuations, will be rolled out nationwide this storm season.

To read the rest of this story, go to the New Orleans Advocate.

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