The US Gulf Coast is bracing for back-to-back tropical cyclones forecast to batter the same communities. Tropical storms Marco and Laura are both on track to slam into Louisiana.
“These storms are not to be taken lightly, especially because there are two of them and they’re going to impact so much of south Louisiana so close together,” Louisiana Governor John Bel Edwards said in a press conference yesterday. Edwards described the storms as a “one-two punch” that would pose a challenge the state has never seen before.
Hurricane Marco was downgraded to a tropical storm as its winds weakened to 70 miles per hour yesterday. Still, the wind will be strong enough to push a wall of water onshore, potentially creating a dangerous storm surge during high tide. That could lead to four-foot-deep flood waters rising along the coast from Morgan City, Louisiana to Ocean Springs, Mississippi. Tornadoes are possible from southeast Louisiana to the western Florida Panhandle.
Tropical Storm Laura is already dangerous: it may spawn a tornado over the Florida Keys today. Laura is expected to strengthen into a hurricane as it barrels over the Gulf of Mexico. It might make landfall as a Category 2 or 3 storm, with wind speeds surpassing 96 miles per hour, in Louisiana on Wednesday. Rain is a risk as well as wind. Flash flooding could be a problem Wednesday through Friday. The forecast calls for four to eight inches of rain throughout the Gulf Coast — but some areas near the Texas and Louisiana border may be hit with 12 inches of rainfall from Laura.
The US narrowly avoided a frightening first this week: two hurricanes in the Gulf of Mexico at the same time. To have two tropical cyclones, an umbrella term for hurricanes and weaker tropical storms, wreaking havoc so near each other is still rare. The last time it happened was 2004, when Hurricane Charley struck southwest Florida as a Category 4 less than a day after Tropical Storm Bonnie swept over the Florida panhandle. The other record of two close hurricanes making landfall in the US dates to September 1933, when the Great Cuba-Brownsville Hurricane pummeled Brownsville, Texas within a day of the Treasure Coast Hurricane hitting Jupiter, Florida with roughly the same Category 3 strength.
Marco and Laura are projected for closer paths than either of their double-hurricane predecessors — damage from both storms could fall on the same communities. The National Hurricane Center this morning warned that Laura could bring “a prolonged period of hazardous weather for areas that are likely to be affected by Marco.”
Louisiana residents were told yesterday by their governor that they had until sundown to get to where they’d shelter from both Marco and Laura. There might not be enough time between storms, he said, for emergency responders to offer much help. Search and rescue parties may not be able to search for survivors, and if they do, they’d have a short window. If Marco knocks out power, there’s a good chance those outages will stretch throughout the duration of Laura, he warned. President Donald Trump approved an emergency disaster declaration for Louisiana yesterday, making federal aid available for state, local, and tribal response efforts.
Storm surge and hurricane watches will likely be issued later today for #Laura. There is an increasing risk of dangerous storm surge, wind, & rainfall impacts from the upper TX coast through the north-central Gulf Coast beginning Wednesday.
Have a hurricane plan in place. pic.twitter.com/bYVd9DPu56
— National Weather Service (@NWS) August 24, 2020
It’s too soon to know whether climate change increased the likelihood of Laura and Marco developing so close to each other. But rising temperatures associated with climate change can create larger areas of ocean where there’s a deep enough layer of warm water for hurricanes to form and intensify, according to John Knox, professor of geography and undergraduate coordinator of the atmospheric sciences program at the University of Georgia.
The 2020 hurricane season has already been unusually active. Marco is already the 13th named storm, and we haven’t even reached the middle of the season. There are typically only about a dozen named storms in an average hurricane season, which ends on November 30th, but forecasters expect up to 25 this year. “Even if this [event] doesn’t turn out so bad for where you’re at, that doesn’t mean you’re in the clear,” says Joel Cline, a tropical program coordinator at the National Oceanic and Atmospheric Administration. “There’s still a lot more season left.”