Tropical Storm — Cameron, Texas

2010-09-06 to 2010-09-07 · Cameron, Texas

Event narrative

Hermine arrived in fits and starts, with frequent gusty feeder band showers followed by relatively calm conditions through the day and early evening of September 6th. Between 830 and 9 PM CST, the action got underway as the central core of Hermine brought a rapid increase in sustained winds and gusts, along with increasingly heavy rainfall. Between 10 PM and 11 PM CST, the northern doughnut crossed the Rio Grande over lower populated southwest Cameron County. Meanwhile, intense feeder bands east of the center, where some of the strongest winds were sampled, pounded Brownsville with sustained winds of 40 to 55 mph and gusts as high as 69 mph at the Brownsville/SPI International Airport. Between midnight and 1230 AM, a very intense band would reform around the center, curling from just south of Harlingen to north of Brownsville. This band would cross Harlingen just prior to 1 AM, and produced near hurricane force gusts (72.5 mph) along with brief sustained winds of 59 mph (at 1158 and 1159 PM CST, respectively), which damaged a number of roofs, knocked down limbs and uprooted trees, and wiped out power to more than 14,000 residents, many in the Harlingen/San Benito area. In all, between 46,000 and 50,000 customers in Cameron County were without power during the peak of the storm, including those in the AEP Texas, Brownsville PUB, and Magic Valley Electric Co-op service areas.

After the inner core of Hermine sliced through, winds quickly diminished below tropical storm force from south to north across the county, between 1230 AM CST near the river and 130 CST near the Willacy County line.

Significant damage included roof collapses to at least one apartment complex in Brownsville, and the La Casita apartments in Harlingen, displacing at least two families. A large part of an industrial building roof collapsed in north Harlingen, and other poorly constructed lightweight roofs were blown off in Brownsville and the Port of Brownsville. Hundreds of medium to large tree limbs fell along the Highway 77 corridor from Brownsville through San Benito and the central and east side of Harlingen.

Boaters, particularly Mexican shrimping vessels, did their best to seek refuge in the Port of Brownsville prior to the arrival of the storm. The sharp increase in east winds ahead of the center's arrival drove breaking waves down the 17 mile Brownsville ship channel; some waves broke as high as the windows of the Harbormaster office. Sixty'four vessels reached the Port, but 5 others became stranded at the coast, including three running aground in Texas and two in Mexico when buoys floated toward the beach and guided the boats toward the rocks. Each boat was able to beach safely, with no human casualties.

Wider weather episode

A persistent are of showers and thunderstorms over the extreme southwestern Gulf of Mexico east of the City of Veracruz, Mexico, during the early morning hours of Sunday, September 5th, 2010, gradually organized into Tropical Depression Number 10 shortly after sunset. Convection increased overnight on the 5th and into the early morning hours of Monday, September 6th, as the system began moving northward, and Tropical Storm Hermine was born at 4 AM CDT on the 6th. Hermine tracked steadily north'northwestward while gradually intensifying on the 6th, reaching the coast of northeastern Tamaulipas State, Mexico, about 40 miles south of Brownsville at 830 PM CDT with peak sustained winds estimated at 65 mph.

Hermine would track to the north'northwest at a steady 14 mph, with the center of circulation crossing the Rio Grande near Los Indios (Cameron County) at around midnight on Tuesday, September 7th. The center reached Harlingen at around 1 AM, Raymondville at around 2 AM, and progressed through the west portion of the King Ranch before exiting Deep South Texas near Falfurrias at around 5 AM. During that time, peak 1 minute sustained winds around the east periphery of the cyclone lessened only slightly, falling from 60 to 50 mph.

A swath of damaging winds and flooding rains pounded Brownsville, Harlingen, and Raymondville as the eyewall of Hermine tracked along and east of Federal Highway 77 in Cameron and Willacy Counties. Peak wind gusts reached or exceeded 70 mph, causing widespread damage to trees and power lines. Rainfall of more than 3 inches in just a few hours flooded roads and farmland, especially in a small swath from northeast Cameron County to southern Willacy County. More than 250,000 residents were impacted by the core of Hermine during the middle of the night, making for a memorable end to the Labor Day weekend. The rapid movement and small core did not allow enough water to build up to a true storm surge in Cameron and Willacy County; tide departures peaked around 1.5 feet which produced run-up to the dune line and closed the county beach access points on South Padre Island to vehicular traffic.

Hermine's near-hurricane force gust punch knocked down hundreds of tree limbs, tore off a number of roofs, blew down dozens of fences, and knocked power out to more than 55,000 area residents during the peak of the storm. In all, several millions of dollars in damage likely occurred to structures in the path of the core circulation of Hermine, including the inner eye wall and next level of core circulation on the east side of the center, which produced tropical storm force winds toward the coastline and into the Lower Texas Gulf waters. A federal emergency was declared for Cameron, Willacy, and Kenedy County based on initial impacts. Final damage statistics will be available later in autumn, 2010.

Source: NOAA Storm Events Database, event_id 251967. Narrative written by the NWS forecast office that issued the report.