Mandatory evacuations as Tropical Storm Barry threatens to flood New Orleans

Tropical Storm Barry is on track to hit New Orleans, dragging slowly across the region, bringing with it a strong storm surge, and dropping as much as two feet of rain at the same time the city is already suffering from river flooding. The potential for disaster has already generated state of emergency declarations in Jefferson, Plaquemines, Orleans, St. Bernard, and St. Charles parishes. Both Jefferson Parish and Plaquemines Parish have issued mandatory evacuations for areas outside the protection of levees.

So far in this nascent hurricane season, high-altitude winds have prevented the development of the kind of tropical cyclones that went on to become major storms in 2017 and 2018. Which is good, because the water in the Gulf of Mexico is insanely warm—as warm as it usually gets in the hottest days of late summer—meaning that any storm that enters the Gulf is likely to get the kind of major intensity boost that turned Hurricane Michael into the most powerful storm ever to strike the Florida Panhandle. And that energy is great enough that it’s turning even what appears to be a rather run-of-the-mill, disorganized storm into a threat that may reach hurricane level before it reaches shore.

On Friday morning, Tropical Storm Barry was carrying peak winds of just 50 mph, well short of hurricane levels. It does not appear that the storm will intensify to hurricane levels before making landfall. However, the storm is continuing to gather moisture as it moves slowly north, and the greatest threat comes not from winds, but from the sheer amount of potential storm surge and rainfall distributed by a storm that is expected to creep across the region for days. That combination of slow movement and high moisture mimics the behavior of Hurricane Florence in 2018. It also happens to be exactly the kind of storm that several models of the climate crisis have predicted will become more common.

But it’s not the storm alone that is threatening the Big Easy. Record floods that scoured the Midwest throughout the spring are still lingering in the form of high water levels in streams and rivers along the lower Mississippi. And another line of storms swept through the region on Wednesday, generating flash floods that left many streets running ankle-deep with water. The Mississippi River at New Orleans is currently 10 feet above its normal level. With some streets already flooded, and levees strained by the persistent high water, Tropical Storm Barry is hitting a city already poised for disaster.

It’s enough to bring out what has become the most-used phrase of the year when it comes to weather events—an unprecedented problem.

Barry is currently tracking toward New Orleans at a sedate pace of just 5 mph. That slow movement means that people in the face of the storm have the time to leave, though most cities and parishes in the region are not mandating evacuation. Most evacuation procedures contemplate leaving in the face of a hurricane of Category 3 or greater bringing high winds and destruction. That’s not the kind of risk that Barry represents.

The slow approach and low winds mean that the surge carried by the storm is expected to be two to six feet—which seems like nothing compared to the jaw-dropping surge that came ashore in the region with Hurricane Katrina. However, the timing of the surge with Barry creates the possibility of merging that effect with high tide, and all that water will be sending waves inland along rivers and streams that are already threatening to overtop banks and levees.

Then there’s the rain. Barry is expected to drop 10 to 20 inches over a wide region, and two feet or more in a few spots. And again, all that water is falling in a basin that is already full to overflowing. That rain is expected to “lead to dangerous, life-threatening flooding over portions of the
central Gulf Coast into the Lower Mississippi Valley.” The news over the weekend will be featuring shots of cars floating along flooded streets and stranded homeowners sitting on their roofs. Again.

What else it will mean is hard to predict. Because everything is. This is the climate crisis: Mankind has moved into a climate regime that has never been seen in the million-year history of the species. Climate models can tell us something about the broad scale of what we can expect: more floods, more fires, and more storms like Florence and Barry that simply drop huge amounts of rain. 

But those models don’t really get down to examining the level of individual human misery.

Friday, Jul 12, 2019 · 2:50:48 PM +00:00 · Mark Sumner

The latest advisory suggests that Barry is strengthening. Sustained wind speeds are up to 65 mph and rising.

Despite earlier predictions that the storm had leveled off, be prepared for the term “Hurricane Barry.”

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