Structural|Engineer|Foundation|Inspection|Licensed|San Antonio|Texas

The 2008 Atlantic hurricane season was the third most costly on record. With damages exceeding $29 billion in the United States alone, it was the fourth busiest year since 1944 and the only year on record in which a major hurricane existed in every month from July through November in the North Atlantic. Of the sixteen named storms during the 2008 hurricane season, Ike was the most powerful. At one point, the diameter of Ike’s tropical storm and hurricane force winds were 600 and 240 miles, respectively, making Ike the largest Atlantic hurricane ever recorded. As the most destructive storm in the Atlantic basin in 2008, Ike made its landfall along the north end of Galveston Island on September 13, 2008 as a Category 2 hurricane.

Ike produced a storm surge of over twelve feet from Galveston Island eastward into southern Louisiana. Bearing the brunt of the surge, the Bolivar Peninsula saw the most extensive property damage, followed by the Galveston Island, Port Arthur, and Houston areas. As is typical for slow moving cyclones, Ike exacted widespread property damage and flooding as it tracked a northwesterly heading through Galveston Bay, about fourteen nautical miles east of downtown Houston, Texas.

As Ike moved slowly through the Houston area, it rendered much of the city’s power grid inoperable. Flooding and wind damage to various buildings and structures were both indiscriminate and wide spread throughout the affected metropolitan area. Ike’s massive size coupled with its record strength delivered a potent combination of torrential rains driven by wind gusts of up to 80-90 mph, placing excessive loads onto many building roof systems along its path, including urban and suburban dwellings. Ike is registered as the most destructive hurricane in Texas history.

Hurricane Ike had a large circulation center with an expansive wind field. Ike’s accumulated cyclone energy (ACE) was the highest registered of any 2008 hurricane. With an integrated kinetic energy exceeding any Atlantic storm on record, Ike neither strengthened nor weakened in the three hours preceding its landfall. Indeed, Ike’s winds persisted at tropical storm and hurricane force velocities near its center for no less than nine hours after its landfall. As Ike moved along its northwesterly inland path on September 13, 2008, the tropical cyclone delivered a potent combination of torrential rains driven by sustained winds of about 69 mph, and wind gusts of up to 90 mph onto many buildings. The nexus of high wind velocities and intense rainfall over an extended time period provided both the means and opportunity for wind caused roof system damage and wind driven moisture intrusion into previously water tight building envelopes and building interiors.

Ike’s relatively long post-landfall duration visited unrelenting wind pressure and rainfall onto building surfaces, including their roof covering systems. Battered by the wind, and saturated by heavy rain, many building roof coverings, wall materials, and metal carport materials either displaced, deflected, or detached completely. Decoupled and displaced asphalt roof covering components subsequently exposed underlying wood roof layers to hydraulically loaded wind driven rain. Wind driven rain impacted unprotected wood material surfaces, pushing moisture into the previously water tight roof component gaps and spaces. Once breached, roof systems and building surfaces allowed the free flow of rainwater into the vulnerable building interior spaces below. This wind driven water intrusion caused exterior and interior material damage both above and below building roof planes.

Ike eventually weakened to a tropical storm by by September 13, 2008 just east of Palestine, Texas, and then became extratropical when it interacted with a front about 12 hours later while moving northeastward through northern Arkansas and southern Missouri. The vigorous extratropical low moved quickly northeastward, producing hurricane-force wind gusts across the Ohio Valley on the afternoon of September 14, 2008. Thereafter, the low weakened and moved across southern Ontario and southern Québec and was absorbed by another area of low pressure near the St. Lawrence River by September 15, 2008.