Hurricane Isaac Floods Homes Near New Orleans

Isaac is part of a new type of hurricane, a type that we've seen only in the past few years which does its damage not with wind but with water. When I read the NHC site a half hour ago, top winds were only 70kt (80mph)... a category 1 hurricane... and not a very strong one at that.

But Isaac's span of coastline is huge, and its motion is slow, when it moves at all. That means two things: massive storm surge and overwhelming flooding. From NBC News:

Updated at 11 a.m. ET: New Orleans' levees and pumps were holding up to the rain and storm surge caused by Hurricane Isaac, but areas outside the defense network saw flooding, including an 18-mile stretch to the south where up to 12 feet of water invaded streets and homes.

Officials in Plaquemines Parish, where the surge overtopped an 8-foot levee, said National Guardsmen and even residents were trying to rescue people trapped in homes. Up to 60 people appear to be trapped, NBC's Gabe Gutierrez reported from the area. Rescuers earlier pulled several dozen to safety.

"We have flooding, inundated four-to-nine feet in areas on that side" of the levee, parish emergency management official Guy Laigast told the Weather Channel. "We've got homes that have been inundated. We have folks who are trapped in their residences."

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My heart goes out to those people. We coast-dwellers build in areas vulnerable to storm surge for very persuasive economic reasons and recreational convenience, but once in a while, we pay the price. My expectation is that the phenomenon "it's the water, not the wind" will prevail more and more often in the near future. Look for "storm surge exceedance" among the products on the NHS site.