US: Authorities order residents in low-lying areas of Louisiana's coast to evacuate ahead of Storms Marco and Laura August 23 /update 1

Event

Authorities in Louisiana's coastal Lafourche Parish ordered a mandatory evacuation for residents of low-lying areas at 12:00 (local time) on Sunday, August 23, ahead of the forecasted impacts of Tropical Storms Marco and Laura. Voluntary evacuations were also issued for parts of Jefferson Parish on Saturday night, August 22. The US Coast Guard has raised its warning for the Port of New Orleans, ordering vessels to make plans to evacuate some areas. Tulane University in New Orleans announced on Sunday that it will close its testing center on Monday, August 24, due to potential flooding and power outages. In Grand Isle, authorities erected sandbags in order to mitigate possible flooding. Furthermore, several energy companies have ordered employees back from offshore oil rigs and ceased production in areas of the Gulf of Mexico. Oil producers had reportedly shut 13 percent of the region's offshore oil production on August 22; the region accounts for approximately 17 percent of total US oil production and 5 percent of US natural gas output.

Currently, Storm Marco is forecast to impact Louisiana on August 24, bringing hurricane-force winds, whilst Storm Laura will reportedly impact areas of the state on Thursday, August 27, possibly strengthening into a hurricane.

Tropical storm watches were issued for parts of Alabama, Florida, Louisiana, and Mississippi on August 22, as Storm Laura continues to track northwest through the Caribbean. The National Hurricane Center (NHC) issued a tropical watch for the Florida Keys between Ocean Reef, Key West, and the Dry Tortugas, in addition to Florida Bay. Tropical storm conditions are expected to affect the Florida Keys from August 24, as Laura moves into the Gulf of Mexico. The National Weather Service (NWS) also issued tropical storm and hurricane watches for coastal areas of Alabama, the western Florida Panhandle, Louisiana, and Mississippi as Laura is expected to bring heavy rain, minor coastal flooding, and wind gusts between Monday, and Tuesday, August 25. Authorities in Monroe county (Florida) issued a state of local emergency on Friday, August 21, and issued mandatory evacuation orders for liveaboard vessels mobile homes and travel trailers.

Tropical Storm Laura moved away from Puerto Rico on late August 22, as it tracks westwards towards southern Hispaniola and Cuba and is expected to move into the Gulf of Mexico on August 23.

Heavy rainfall and associated flooding are possible over the coming days, along with associated disruptions to business and transport.

Context

The Atlantic hurricane season runs from late May through to the end of November, with activity typically peaking in late August and early September. Numerous tropical storms form in the Atlantic Ocean during this period, with most affecting the Caribbean, the Gulf of Mexico, and the east coast of the United States. Although communities in the region are generally well prepared for adverse weather conditions during the hurricane season, severe storms bring a significant risk of flooding and infrastructural damage.

The country's Eastern and Gulf seaboards are vulnerable to tropical systems during hurricane season (June - November), although the southeast from Texas through Virginia is most at risk of a direct impact from a strong storm. Changing weather patterns in recent years have also resulted in severe flooding in areas previously unfamiliar with such events, and many have faulted global warming.

Advice

Those in the affected areas are advised to monitor local weather reports, avoid areas directly affected by flooding, confirm road conditions before setting out, and adhere to instructions issued by local authorities.