Tropical Storm Laura’s flooding and other impacts on the ground: What we know
Tropical Storm Laura, which has been downgraded from a hurricane, made landfall early Thursday morning in Cameron, Louisiana — just 35 miles east of the Texas-Louisiana border — as a Category 4 storm with 150 mph winds.
Already, pictures and videos of the storm from Lake Charles, Louisiana, a town about 50 miles north of Cameron, show torn-off roofs, downed power lines, blown-out windows, and dozens of trees ripped from the ground.
Louisiana Gov. John Bel Edwards said he’d received a report Thursday morning of the first American fatality from Laura, a 14-year-old girl from Vernon Parish who died when a tree fell on her home. Edwards later said a total of four people in his state have died — all as a result of fallen trees. Laura was also responsible for at least 23 deaths in Haiti and the Dominican Republic earlier this week.
There has been no official word of other injuries or deaths in the US since the storm made landfall. What we know is that about 20 million people reside in the path of the storm and 500,000 have been ordered to evacuate, a task complicated by the Covid-19 pandemic.
And so far, more than 740,000 homes and businesses are without power in Texas and Louisiana.
Louisiana and Texas residents were warned the storm surge could be “unsurvivable”
As a Category 4 hurricane, Laura reportedly became the strongest storm on record to make landfall along the western Louisiana and northern Texas coast. Although the storm has weakened since moving inland, prompting its downgrade from hurricane status, it is still sustaining winds of 52 mph.
Hurricane-force winds can cause normally dry areas near the coast to be flooded by rising waters. The National Hurricane Center (NHC) predicted that this phenomenon, referred to as “storm surge,” could result in up to 20 feet of flooding in places within 40 miles of shoreline where Laura made landfall, rendering some areas “unsurvivable” and resulting in “catastrophic damage.” However, it appears as if a slight change in wind direction may have spared the worst-hit areas from the feared 20-foot surge.
The NHC said Thursday the worst of the initial storm surge hit communities directly east of Cameron, which are experiencing surge of around 9 feet.
Some meteorologists, however, warn against jumping to premature conclusions about the extent of storm surge from Hurricane Laura, considering the limited number of data points currently available.
Heavy rain is also predicted to be widespread across the west-central Gulf Coast, with 5 to 10 inches falling over a broad area, and up to 18 inches locally. And this rain is expected to result in flash flooding throughout the region.
After making landfall Thursday morning, Laura tracked north across Louisiana throughout the day, and its center is expected to move into Arkansas overnight. The storm will then move through the Tennessee Valley and the mid-Atlantic from Friday into Saturday. As of now, the NHC predicts the storm will continue to give off heavy rain and sustain winds between 30 and 40 mph.
One of the most powerful storms in US history
Meteorologists categorize hurricanes based on the intensity of storms’ maximum sustained winds:
- Category 1: 74-95 mph (a storm with winds below 74 mph is classified as a “tropical storm,” and below 38 mph is a “tropical depression”)
- Category 2: 96-110 mph
- Category 3: 111-129 mph
- Category 4: 130-156 mph
- Category 5: 157 mph or higher
Laura’s 150 mph winds at landfall made it a Category 4 hurricane and one of the most powerful in US history — as powerful as Hurricane Charley in 2004 and slightly less powerful than Hurricane Michael in 2018, but far more powerful than Hurricane Katrina (which clocked in at 125 mph at landfall) in 2005.
These categorizations are important in terms of assessing potential damage to life and property. From 1900 to 2005, US hurricanes that clocked in at category 3, 4, and 5 at landfall have been responsible for 85 percent of total hurricane damage, despite making up around a quarter of total hurricanes. That’s because relatively small changes in wind speeds can lead to exponentially more damage. For instance, hurricanes like Laura that make landfall at around 150 mph cause, on average, 256 times more damage than hurricanes less than half their speed, at 75 mph, would.
But wind speed alone doesn’t determine how deadly a hurricane will be. As my colleagues Brian Resnick and Eliza Barclay explain, storm surge, the coastal flooding that occurs when a storm’s winds push water onshore several feet above the normal tide, is particularly dangerous. Severe storm surge — like that expected with Laura — can trap people in their homes, wash away houses, and make rescue missions harrowing and slow.
So far, we don’t know what the damage from Tropical Storm Laura will be, but we do have reference points. Hurricane Rita, which hit the same area as Laura in 2005, produced up to 15 feet of storm surge, had Category 3 winds of 115 mph, and resulted in 97 to 125 deaths and $18.5 billion in damage. By comparison, Laura made landfall with Category 4 winds of 150 mph and is predicted to produce up to 20 feet of storm surge.
A record season for hurricanes
Laura is the 12th of as many as 25 named storms that the National Oceanic and Atmospheric Administration (NOAA) has predicted would form this hurricane season (which lasts from June 1 to November 30); seven to 11 of those storms, including Laura, were expected to become hurricanes. If NOAA’s predictions are correct, this will be a record-breaking season for hurricanes.
“This is one of the most active seasonal forecasts that NOAA has produced in its 22-year history of hurricane outlooks. NOAA will continue to provide the best possible science and service to communities across the Nation for the remainder of hurricane season to ensure public readiness and safety,” said Commerce Secretary Wilbur Ross, who oversees the agency. “We encourage all Americans to do their part by getting prepared, remaining vigilant, and being ready to take action when necessary.”
There are a few explanations for this record-breaking season, but chief among them are the above-average sea surface temperatures in the tropical Atlantic Ocean and Caribbean Sea, particularly in the region between West Africa and the Leeward Islands, which tends to be a prime development region for hurricanes.
These warmer-than-average waters are, in part, the result of climate change. A new study published earlier this year in the Proceedings of the National Academy of Sciences by a group of NOAA and University of Wisconsin Madison researchers found that from 1979 to 2017, the odds that a given tropical cyclone would become a Category 3, 4 or 5 hurricane increased about 8 percent per decade as the planet has warmed.
This finding builds on lots of previous research — like multiple academic studies demonstrating that Hurricane Harvey’s record-blasting rains were likely amplified by climate change.
“We’ve just increased our confidence of our understanding of the link between hurricane intensity and climate change,” James Kossin, the lead author of the new study, told the Washington Post. “We have high confidence that there is a human fingerprint on these changes.”
In other words, Laura might be the most recent of the major hurricanes to reach US shores, but it certainly won’t be the last.
How to follow Tropical Storm Laura:
- The National Hurricane Center provides updates every few hours, with projections and important warnings. Take a look here.
- The National Hurricane Center’s Twitter account has similar updates, as well as the latest on forecast changes and public safety concerns.
- Meteorologist and journalist Eric Holthaus has compiled a Twitter list of weather experts that’s a valuable repository of forecasts, data, and useful information on hurricanes in general.
Correction, August 26: An earlier version of this story misstated the relative strength of Hurricanes Michael and Charley.
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