Storm Surge/Tide — Coastal Cameron, Texas

2008-07-23 · Coastal Cameron, Texas

Event narrative

The intensification of the western and southern eyewall of Dolly brought hurricane force west winds, which blew tides out sharply along east-facing shorelines by early afternoon. Unfortunately, the same situation that spared both Port Isabel and nearby communities on the east facing side of Laguna Madre, as well as the beachfront structures on South Padre Island, allowed bayside flooding to develop along the west facing shoreline of South Padre Island, as an estimated 4 foot surge pounded through Laguna Boulevard, and continued across Padre Boulevard, even reaching Gulf Boulevard at time of highest impact, between 1 and 130 PM CDT. Buildings on stilts and pilings fared well, while others may have sustained some inundation flooding, which likely combined with some freshwater flooding due to blinding rains associated with the most intense period of the storm, generally between 11 and 2 PM CDT.

Conditions improved later in the afternoon as winds continued to back to the southwest, then south, and drop off markedly in speed.

Wider weather episode

Hurricane Dolly, the first storm since Bret (1999) to make landfall along the Deep South Texas barrier islands, left a trail of widespread minor to moderate structural and natural damage across much of the Lower Rio Grande Valley and Deep South Texas on July 23rd, and dumped copious rainfall across the area, causing numerous instances of flooding primarily of low lying and poor drainage locations, as well as filling local resacas and arroyos, and causing notable rises on larger area creeks and rivers. Dolly intensified rapidly to an estimated minimum pressure of 962 mb while drifting northward just east of South Padre Island, and its center made landfall between 1 and 2 PM on July 23rd along the unpopulated shoreline of Cameron and Willacy County. Dolly then eased westward across southern Willacy County through the afternoon, continued into extreme northern Hidalgo County as a tropical storm during the evening, then turned northwest and accelerated through Jim Hogg County during the early morning hours of the 24th, passing into Webb County shortly after sunrise.

The strong winds and heavy rains contributed to widespread power outages in the Lower Rio Grande Valley, where at least 236,000 customers lost power, but possibly upwards of 250,000 - primarily across the more populated regions of Cameron, Hidalgo, and Willacy County. Agricultural experts deemed a substantial loss of cotton and sorghum due to the strong winds and torrential rain. As of the end of Calendar Year 2008, estimated insured property damage (wind) based on the standard doubling of insurance estimates from the Property Claims Service of the Insurance Services Office was $1.05 billion. Reported insured flood damage from FEMA's National Flood Insurance Program is $171 thousand; however, it is estimated that the vast majority of flood damage occurred to uninsured properties, and a rough estimate of total flood damage, which was more widespread, and includes agricultural losses, will likely push total flood-related damages to between $100 and $300 million.

It is conceivable that total damage from all Hurricane Dolly related hazards may have exceeded $1.5 billion.

More than 6,000 Lower Rio Grande Valley residents were housed in temporary shelters from Deep South Texas to San Antonio at the peak of the storm; 13,000 residents across the Lower Rio Grande Valley visited FEMA Disaster Recovery Centers after the storm. As of October 3rd, FEMA had distributed $44 million in relief; $30 million to individual households, nearly $10 million to small businesses through the Small Business Administration, and just under $5 million to local governments for infrastructure repair.

Please note that best estimates will be included on a county by county basis as data is received through the rest of the year.

Storm total rainfall from the evening of July 22nd through the early afternoon of July 24th generally ranged from 4 to 10 inches in Kenedy, Brooks, Starr, Jim Hogg, and Zapata Counties, and 6 to 14 inches in Hidalgo, Willacy, and Cameron Counties, with locally more than 18 inches possible in the persistent southern eyewall in northern Cameron and southern Willacy Counties. Widespread freshwater flooding occurred in these areas as Dolly moved through, and low lying, poor drainage, or areas where drainage systems failed were flooded for days, and in some cases weeks, to come.

The late intensification of Dolly just prior to landfall, combined with a brief northward jog before turning to the west along the Cameron/Willacy County line, limited Gulf storm surge effects across the Town of South Padre Island through mid morning on the 23rd. However, hurricane force west winds whipped an estimated 3 to 4 foot water rise from Laguna Madre across the Town, with water briefly stretching across the Island at the height of the event. The town of Port Mansfield, immediately north of the center, estimated a 4 foot storm surge and 5 foot storm tide.

Interestingly, tides to the north of Dolly's center initially fell to below predicted values on increasing northerly winds, before rising during the late afternoon and evening as the cyclone moved inland, and strong southerly flow piled a storm tide of up to 6 feet above Mean Lower Low Water (MLLW) along the uninhabited Kenedy County shoreline.

There was a single confirmed tornado in Cameron County during the late evening of July 22nd, associated with one of the first outer rain bands. No damage was reported.

Source: NOAA Storm Events Database, event_id 130312. Narrative written by the NWS forecast office that issued the report.