Hurricane Nicholas Swamped the Gulf Coast With Storm Surge, Rainfall Flooding (RECAP)

Nicholas became the 14th named storm of the 2021 Atlantic hurricane season on Sept. 12 over the southwest Gulf of Mexico.

The following night, Nicholas strengthened into the sixth hurricane of the season just off the Texas coast.

It made landfall just northeast of Matagorda Bay, Texas, less than 3 hours later as a Category 1 hurricane with maximum sustained winds of 75 mph.

Winds

The upgrade to hurricane strength was prompted by a WeatherFlow sensor at Matagorda Bay, Texas, which recorded sustained winds of 76 mph and a gust to 95 mph.

Several other locations along the Texas coast clocked wind gusts at least to 60 mph including a 77-mph gust at Palacios.

Port O'Connor, Texas, measured gusts up to 75 mph, and water levels rose quickly, with 3 feet of inundation, according to a NOAA gauge.

In the Houston metro, winds gusted over 50 mph in several locations, and a 63 mph gust was clocked at the University of Houston.

At its peak, more than 500,000 homes and businesses were without power in southeast Texas, including the Houston area, according to poweroutage.us.

A few wind gusts from 40 to 50 mph were clocked near the Louisiana and Mississippi coasts, as well, according to the National Weather Service.

Storm Surge

Storm surge and rainfall flooding prompted the closure of the only road from Matagorda to Matagorda Beach, Texas.

Storm surge of 3 to 6 feet above normal tide levels was observed on the upper Texas coast, with the highest surge around Galveston Bay.

Heavy Rain/Flooding

Flooding rain first closed some roads in Corpus Christi while Nicholas was still offshore.

By the morning after landfall, over a dozen stretches of Houston metro freeways were flooded, including Highway 225 in Pasadena and stretches of Interstate 45.

Some areas of high water were reported on feeder roads adjacent to the Gulf Freeway (Interstate 45) in Galveston County and on Broadway in the city of Galveston, according to the National Weather Service.

Rainfall in Houston ranged from 1 to 3 inches on the metro's west side to locally over 6 inches in the east and south metro. Deer Park, Texas, which is located just east of Houston, had the highest believable storm total rainfall in the metro with 9.85 inches.

Water flooded several roads in and near Beaumont and Orange, Texas, a pair of east Texas cities ravaged by flooding from Tropical Storm Imelda in 2019 and Harvey in 2017.

In Louisiana, isolated heavy rain well ahead of Nicholas triggered street flooding in East Baton Rouge, Louisiana, on Sept. 13, before Nicholas made landfall in Texas.

Bands of heavy rain also triggered street flooding in New Orleans. Multiple underpasses were reported impassable in New Orleans East.

Debris from Hurricane Ida blocking ditches and storm drains, not to mention saturated ground, contributed to flash flooding in southeast Louisiana from Nicholas, according to the NWS office in Slidell, Louisiana.

Heavy rain flooded roads in several areas on Sept. 15, including Livingston Parish, Louisiana, Gulfport, Mississippi, Bayou La Batre, Alabama, and Pensacola, Florida.

In Baldwin County, Alabama, the heavy rain triggered a sinkhole near Seminole, according to local emergency management.

In general, 4 to 10 inches of rain fell near the middle and upper Texas coast, 5 to 9 inches in southern Louisiana, 4 to 8 inches in southern Mississippi, 4 to 7 inches in southern Alabama and 2 to 9 inches over the far western Florida Panhandle.

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