Beta to unleash days of flooding rainfall, pounding surf from Texas to Louisiana

Beta became the ninth named storm to make landfall in the United States on Monday night, after coming ashore along the Texas coast near the southern end of the Matagorda Peninsula, close to Port O'Connor, with maximum sustained winds of 45 mph. Well ahead of landfall, the storm's wrath was felt along the storm-battered Gulf Coast over the weekend.

Beta has weakened to a tropical depression as of 10 a.m. CDT Tuesday. Further weakening to a tropical rainstorm is anticipated in the coming days, but torrential rainfall and flooding will continue along a portion of its slow-moving path.

Communities that were devastated by Hurricane Laura, and to some extent more recently by Hurricane Sally, could face strong winds and downpours that could hinder ongoing recovery efforts. AccuWeather forecasters have rated Beta a 1 on the AccuWeather RealImpact™ Scale for Hurricanes.  

Texas Gov. Greg Abbott issued a disaster declaration for 29 counties in Texas on Monday as Beta churned toward the coast.

On Sunday evening, pummeling waves generated by the storm destroyed part of the 61st Street Pier in Galveston, Texas, a coastal town south and east of Houston. Webcam footage captured workers trying to save as much of the pier as possible as waves battered the structure. Part of the fishing pier was found several miles away on Monday morning, KHOU 11 reported. 

Heavy rainfall from Beta is seen dousing the Texas coastline as the tropical storm makes landfall on Monday night. (AccuWeather)

Even as far away as Louisiana, the storm was churning up rough surf and causing flooding over the weekend. Lakeshore Drive in New Orleans was closed on Sunday as water levels climbed on Lake Pontchartrain. Video showed the choppy waters on the lake, even as the storm swirled off of Texas over the western Gulf of Mexico. Coastal flooding continued on Monday with some roads inundated and impassible. Flash flood watches were in effect in the city in advance of the storm’s excessive rainfall.  

Louisiana Gov. John Bel Edwards declared a state of emergency ahead of the tropical storm on Monday, opening up state resources to aid in local government response. He warned that the storm's slow movement puts the southwestern part of the state at risk for flooding through at least the middle of the week.

Numerous watches and warnings remain in effect along the coasts of Louisiana and Texas, due to the potential for storm-surge flooding, heavy rainfall and tropical-storm-force winds.

Forecasters and officials are urging residents to not focus on Beta's intensity, and rather on the days of heavy rainfall and flooding that it is likely to unleash, even well away from the center of the storm.

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Widespread rainfall totals of 4-8 inches are expected across southeastern Texas and into southern Louisiana. Higher rainfall totals on the order of 8-16 inches with an AccuWeather Local StormMax™ of 24 inches are expected to occur along the Texas and Louisiana coasts.

Texas Gov. Greg Abbott called on Texans to remain vigilant and heed all advice of local officials on Sunday. "The State of Texas is prepared to support communities in the path of the storm, where substantial amounts of rainfall and flash flooding are a significant threat.We will continue to closely monitor the storm and work collaboratively with officials to ensure our fellow Texans are safe,” he said.

Heavy rainfall and the risk for flash flooding are likely even if the storm wobbles back over the water and lingers just offshore of the Texas coast as currently forecast.

"This rainfall can lead to significant, life-threatening flooding, which may last for several days," AccuWeather Senior Meteorologist Rob Miller said.

Primarily due to the flood threat, Beta will be a 1 for the United States on the AccuWeather RealImpact™ Scale for Hurricanes. The RealImpact™ Scale for Hurricanes is a 6-point scale with ratings of less than 1 and 1 to 5 that was introduced by AccuWeather in 2019 to rate tropical systems based on multiple impacts, rather than just wind, like the Saffir-Simpson Hurricane Wind Scale does.

Even though Beta is not nearly as strong as Hurricane Harvey, which exploded into a Category 4 storm in 2017, it is expected to crawl across the region, and forecasters warn that it will have enough fuel to produce torrential rainfall along its path. In 2017, Harvey unloaded up to 61 inches of rain as it spent days spinning over eastern Texas.

Back in 2001, Allison, as a tropical storm, unleashed disastrous flooding across southeastern Texas, due to its slow movement.

Should the storm stall near the Texas coast, rainfall amounts could be higher and may even exceed 24 inches. Conversely, should Beta move along at a quicker pace or more drier air get pulled into the storm, total rainfall amounts could be cut in half for some locations, though flooding would still remain a threat.

Beta will continue to create a minor to moderate storm surge along the western and central Gulf coast, as well as rough seas, pounding surf and dangerous rip currents over the Gulf of Mexico.

"Tropical Storm Beta is a reminder that hurricane season is still in full swing," Houston Mayor Sylvester Turner said in a media release on Friday. "Now is the time to prepare. Stock your emergency kit, refill prescriptions and monitor Houston OEM's channels for official updates.”

Waterspouts and isolated tornadoes can occur in Beta's outer bands to the northeast of the center of the storm.

An area of 40- to 50-mph wind gusts will extend along the Texas and southwestern Louisiana coasts. An AccuWeather Local StormMax™ of 55 mph is expected closest to where Beta made landfall.

"As high pressure to the north weakens and another upper-level disturbance approaches from the northwest, Beta should take a more northerly [to northeasterly] course during the middle and latter part of the week," Miller said.

Depending on the exact track of Beta, drenching downpours could reach the Southeast later in the week, including areas recently impacted by Hurricane Sally.

Weak steering winds have resulted in Beta meandering over the Gulf of Mexico since last week.

Forecasters had been monitoring the disturbance for over a week before it developed into Tropical Depression 22 on Thursday, Sept. 17. By Friday evening, the system strengthened into Tropical Storm Beta, writing a new page in the record books for becoming the earliest 23rd-named tropical storm in the Atlantic, replacing Alpha from 2005, which formed on Oct. 22 and was the first-ever storm to be named a Greek letter.

The tropical storm claimed the second letter in the Greek alphabet on Friday afternoon, following Wilfred and Alpha. Once the last name on the Atlantic hurricane season's designated list is exhausted, Greek letters are used to identify tropical storms.

Prior to Beta, eight storms had made landfall in the U.S. during the hyperactive 2020 hurricane season. In comparison, 3 to 4 storms typically strike the country during an entire hurricane season. 

With months still left in the Atlantic hurricane season, more Greek letters are likely to be used. Last week, AccuWeather meteorologists upped their 2020 season predictions for the number of total storms to 28, which would tie the record number of named storms in the basin set in the notorious 2005 season.

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