Tropical Storm and Storm Surge in Texas, September 6 to 7, 2010

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.

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 the coastal sections of Cameron County with sustained winds of 45 to 53 mph and gusts as high as 60+ mph at various sites near the coast.

Peak winds included: 53 mph gust 63 mph, Port Isabel C-MAN, 1106 PM CST; 52 mph gust 64 mph, Realitos Peninsula (east of Arroyo City), 1124 PM CST; and 52 mph gust 62 mph, South Padre Island heliport, 1115 PM CST. Damage included numerous downed limbs and power lines; power outages for Coastal Cameron County were estimated to be x thousand by AEP Texas.

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.

Any significant damage will be reported as received by the NWS Office in Brownsville.

Boaters, particularly Mexican shrimping vessels, did their best to seek refuge in the Port of Brownsville prior to the arrival of the storm. 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.

After ripping Harlingen's Valley International Airport with 72.5 mph wind gusts just prior to midnight CST (6 miles south of the Cameron/Willacy county line, the inner core of Hermine waned for a few moments before reintensifying in southern Willacy County, ultimately slamming through Raymondville at around 1 AM with wind gusts estimated just below hurricane force (70 mph). Widespread damage included hundreds of snapped limbs, dozens of uprooted trees, power outages to 75 to 80 per cent of the county, and destruction of several poorly constructed roofs and lean tos. At one home, a trampoline sailed into a window, causing a scratch injury to a 5 year old girl. At a motor hotel along the expressway, roof decking was blown out, forcing 10 guests to escape the facility. Significant injuries were not reported, though at least one of the guests had minor scratches.

Damage was also noted to a few poorly constructed aluminum barns and surrounding trees in south central Willacy County, from 5 miles east of Lyford down FM 507 to near Santa Monica close to the Cameron County line.

AEP Texas reported 4400 customers without power during the peak of the storm.

Feeder bands scraping along the Lower Texas Coast, first producing sustained winds generally around 50 mph gusting to more than 60 mph along and near the Cameron County coastline, scooted through Coastal Willacy County around and a bit after midnight on September 7th. Peak sustained winds of 52 mph gusting to 64 mph at Realitos Peninsula (about 5 to 8 miles south of the county line) likely continued toward the Port Mansfield area (based on winds of 48 gusting to 58 mph at Rincon del San Jose, along the Kenedy County Laguna shoreline 15 miles north of the Willacy/Kenedy County line).

AEP Texas reported 4400 customers without power during the peak of the storm; most were likely in the Raymondville area where structural damage was most severe but there were reports of power outages in Port Mansfield as well.

The core of still-intense Hermine moved along and just west of Federal Highway 77 through the west section of the King Ranch in Kenedy County, likely bringing continued sustained tropical storm force winds between 40 and 50 mph with gusts to 60 mph or higher over the very rural county during the pre dawn hours of September 7th. Farther east, feeder bands continued to produce sustained tropical storm force winds between 40 and 50 mph with gusts near 60 mph, as evidenced by reports at Rincon del San Jose (midway up the Laguna Madre in the county; 48 mph gust 58 mph at 100 CST) and at Baffin Bay Texas Coastal Ocean Observing Network (44 mph gust 56 mph at 324 CST). Observations just prior to sunrise at Kingsville (about 25 miles north of the Kenedy/Kleberg line) indicated peak winds to 63 mph at 523 CST).

Damage has not been estimated in Kenedy County as of this writing.

Torrential and quick hitting rainfall associated with persistent feeder bands around the middle core of Tropical Storm Hermine left widespread farm/field flooding across extreme northeast Cameron County from late night into the pre dawn hours of September 7th. Bias corrected radar estimates, combined with an observed report of 7.73 inches 9.4 miles northeast of Rio Hondo, indicated 6 to 8 inches fell in the area. With most of the fields plowed over, damage from the flooding may have been minimal. However, high standing water was discovered at the edge of FM 507 just across the Willacy County line 12 to 15 hours after the worst of the rains had fallen, indicating a brief period of true flash flooding was likely.

Torrential and quick hitting rainfall associated with persistent feeder bands around the middle core of Tropical Storm Hermine left widespread farm/field flooding across extreme northeast Cameron County from late night into the pre dawn hours of September 7th. Bias corrected radar estimates, combined with an observed report of 7.73 inches 9.4 miles northeast of Rio Hondo, indicated 6 to 8 inches fell in the area on both sides of the northeast Cameron/southeast Willacy County line. With most of the fields plowed over, damage from the flooding may have been minimal. However, high standing water was discovered at the edge of FM 507 just in Willacy County line 12 to 15 hours after the worst of the rains had fallen, indicating a brief period of true flash flooding was likely covering some of the Farm to Market Roads, and a number of unimproved County Roads.

As Hermine quickly scooted along and just west of Federal Highway 77 in Kenedy County, surface winds shifted sharply from east to south, channeling higher tides brought into the Laguna Madre during the evening of September 6th and pushed water levels sharply higher in the thinner portion of the waterway, perhaps starting in Willacy County but definitely observed at both Rincon del San Jose and Baffin Bay (Texas Coastal Ocean Observing Network locations). At Rincon del San Jose, the water level rose over 6 feet and reached nearly 7 feet at around 300 CST - between 3 and 4 feet above predicted levels.

While no flooding was observed - the area is completely undeveloped along the Padre Island Seashore - the surge was notable.

The core of still-intense Hermine moved along and just west of Federal Highway 77 through the west section of the King Ranch in Kenedy County, likely bringing continued sustained tropical storm force winds around 40 mph with gusts to 50 mph or higher over rural northeastern Brooks County during the pre dawn hours of September 7th. There was a sharp drop off in winds to the west of the small core; the Brooks County Airport just east of Falfurrias reported a peak gust just at tropical storm force (39 mph) at 245 AM CST. However, in Jim Wells County, Alice International Airport recorded peak winds of 39 mph with gusts to 54 mph between 440 and 553 AM CST.

Damage has not been estimated in Brooks County as of this writing.