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Isaac Weakens, But the Danger is Far From Over

Tropical Storm Isaac stayed at hurricane strength for only about a day, and it was only a middleweight Category 1 hurricane at that, with sustained winds that only reached 80 mph or so; by Thursday morning, those winds had dropped to 45 mph as the eye lumbered at a leisurely 8 mph on a north by northwesterly path through central Louisiana. By sometime Thursday night or Friday morning, said forecasters at the National Hurricane Center, an even weaker Isaac should be crossing the Louisiana-Arkansas border. While Hurricane Katrina caused more than 1800 deaths when it smashed into New Orleans exactly seven years ago, Isaac had claimed just one fatality as of Thursday morning, a tow truck driver killed by a falling tree late Wednesday night. 

Credit: Google.org Crisis Response

If that makes it sound like Isaac is no big deal, however, think again. The storm’s enormous size extended its reach all the way from the Texas border to the west to the Florida Panhandle to the east. To the east, especially, on Isaac’s leading edge, torrential rains of ten inches — up to more than 20 in isolated spots — and storm surges that reached at least 12 feet in some areas battered residents for an unrelenting 24 hours and more.

As of Thursday morning, forecasters were still warning of dangerous flooding from the 12-18 inches of additional rain still likely to fall in the Lower Mississippi Valley, along with a threat of isolated tornadoes across most of Mississippi, and parts of Louisiana, Arkansas, Alabama and Florida. Along the Louisiana and Mississippi coasts, storm surges are likely to linger into Thursday. High winds and falling trees, meanwhile, knocked out power to nearly 700,000 Louisianans, and many thousands more in neighboring states.

In New Orleans itself, the levees that were rebuilt in the aftermath of Katrina held back the deluge, but areas outside New Orleans were swamped by flooding driven by the storm surge. Hardest hit of all was Plaquemines Parish, which sits on a spit of land that juts precariously out into the Gulf of Mexico. “We’ve never seen anything like this, not even Katrina,” parish president Billy Nungesser, whose own house had its roof ripped away by the winds,  told reporters.

1-5 Day map of expected rainfall (inches) from Tropical Storm Isaac.
Valid August 30-September 4.
Credit: NOAA

As Isaac moves north and, ultimately, northeast, that sort of damage will diminish along with the storm’s diminishing winds. Heavy rains will continue, however, with

Those rains, at least, could be a blessing for parched Arkansas, where significant parts of the state have been suffering extreme drought as part of the nation’s worst dry episode since the 1950’s.

Isaac’s projected path should put it in Missouri by Saturday, Indiana by Sunday and over the Indiana-Ohio border by Labor Day. The storm will be far weaker by then, but forecasters are calling for potentially heavy rains across a wide path through the nation’s midsection. 

It won’t be enough to make up for the summer-long drought, and the rains will come too late to help the corn and soybean crops devastated by the lack of water. But it comes just in time, according to report by Reuters, to give hope for the fall wheat planting season.