Hurricane Harvey: A look at its unique characteristics

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The slow-moving, super-wet and especially devastating storm named Harvey is finally fizzling.

Since first hitting shore near Corpus Christi, US State of Texas, more than a week ago, the storm dumped 27 trillion gallons of rain on Texas and Louisiana – enough to cover all of Manhattan 1.6-kilometer deep. It has set a record for rainfall from a tropical system in the continental US, dropping 1.3 meters just outside Houston. That’s only an eighth of an inch (3.2 millimeters) behind the US record set in Hawaii in 1950.

The deluge damaged an estimated 156,000 dwellings, and parts of Houston may be flooded for another month. The death toll of 44 ranks it as the mainland’s sixth deadliest hurricane in 50 years.

Volunteer rescue boats make their way into a flooded subdivision to rescue stranded residents as floodwaters from Tropical Storm Harvey rise Monday, Aug. 28, 2017, in Spring, Texas. /AP Photo

What made it so bad? Harvey was strange – in how it nearly dissolved once but roared back as a major hurricane, in how it intensified so quickly before hitting land, in how it parked itself over one unfortunate region for so long and, of course, in the amount of rain it generated.

“It had several unique characteristics in terms of its strength and track. And unfortunately, they combined to produce a severe impact over a highly populated area,” National Hurricane Center Acting Director Ed Rappaport said.

Lauren Durst holds onto her ten-month-old son, Wyatt Durst, as they evacuate from the Savannah Estates neighborhood as Addicks Reservoir nears capacity during Tropical Storm Harvey, Tuesday, Aug. 29, 2017, in Houston. /Houston Chronicle via AP

Harvey was born in the Atlantic southeast of Puerto Rico on Aug. 17, then got downgraded to a tropical wave and breezed into Mexico’s Yucatan peninsula with little fanfare. But once Harvey got into the Gulf of Mexico on Aug. 23, it rapidly exploded into a Category 4 hurricane just a few hours before coming ashore, something experts had not seen happen much before.

It was the first Category 4 storm to make landfall in the United States since 2004. Rappaport and others said it will likely rank among the costliest storms to hit the United States. In some ways, it landed in the perfect place to wreak the most havoc. The worst of its rains stayed to the east of its eye and hit very close to the nation’s fourth-largest city, a city that is as flat as a tabletop and especially prone to flooding.

That’s what Harvey will be remembered for, even though coastal cities like Rockport were all but flattened, said University of Miami senior hurricane researcher Brian McNoldy. “They’re going to take backstage to Houston.”

Most hurricanes, including 2005′s Katrina, weaken just before they hit shore. Harvey got much stronger, fueled in part by pockets of extra warm water in the Gulf of Mexico.

“Harvey was the first to go from tropical storm strength to major hurricane strength in its last 36 hours before US landfall,” Rappaport said.

Then it just stuck around.

In this aerial photo, a neighborhood near Addicks Reservoir are flooded by rain from Tropical Storm Harvey Tuesday, Aug. 29, 2017, in Houston. /AP Photo

For more than 130 hours – from 10 a.m. Friday, Aug. 25, through 10 p.m. Wednesday, Aug. 30 – Harvey was raining over some part of eastern Texas. When Harvey did move, including a dip back into the Gulf of Mexico for about a day, it was still close enough to drench Texas.

“It’s extremely rare to have a major hurricane that just sits there after it makes landfall,” McNoldy said.

Volunteer Elizabeth Hill, 8, plays with evacuee Skyler Smith, 7, at a shelter at St. Thomas Presbyterian Church in west Houston as Tropical Storm Harvey continues to affect the area Tuesday, Aug. 29, 2017. /Austin American-Statesman via AP

Usually strong storms blast through an area, dump a foot or so of rain, and move on. But Harvey was stuck between two high-pressure weather systems to the east and west that kept pushing it in opposite directions, so it just staggered in a zig-zag pattern across southeast Texas.

“The sheer area that was inundated by 20 inches (51 centimeters) of rain was unbelievable,” said Jeff Masters, meteorology director of the private forecasting service Weather Underground.

If it had only continued a bit farther, over northern Texas, Harvey would not have been as wet. But by stalling near the coast, the storm was allowed to draw more and more moisture from the gulf and sustain extraordinary rainfall rates, including more than 10 centimeters per hour over the Beaumont-Port Arthur area, Masters said.

Workers begin repairs to a wall that was lost in the wake of Hurricane Harvey, Wednesday, Aug. 30, 2017, in Rockport, Texas. /AP Photo

Finally, after its second US landfall along the Texas-Louisiana border, Harvey started to move on.

It pushed north and east, weakening but still dumping several inches of rain on US states of Mississippi, Alabama, Tennessee, Kentucky, Indiana and North Carolina. By Sunday, forecasters say, the storm’s remnants will look like the regular weather.

Meteorologists are already eyeing another system: Hurricane Irma, which intensified from a tropical storm to a major hurricane in just 30 hours, is steadily moving west across the Atlantic. It’s still several days away from the nearest land just south of Puerto Rico.

Source(s): AP