Twenty-five miles from Galveston Bay and 45 miles from the Gulf of Mexico, the city always has had to defend against storms, both thunderstorms that blow in from the west to swell creeks and rivers and tropical storms that roll in from the Gulf with damaging wind pushing waves and storm surge.
A storm estimated to have had Category 4 winds made landfall at Galveston on Sept. 8, 1900, and became the deadliest U.S. natural disaster, killing as many as 8,000 people. The heaviest rainfall on record in the country, 42 inches, fell on Houston during Tropical Storm Claudette in 1979. In 2001, Allison, the largest tropical storm on record to make U.S. landfall, poured 35 inches of rain on Houston, where floods drowned 27 of the 41 people killed in that storm. Ike in 2008 was the nation’s third-most expensive hurricane, after Katrina in 2005 and Andrew, a Category 5 hurricane when it hit southern Florida in 1992.
Scientists with the U.S. Global Change Research Program estimate that stronger hurricanes are a likely consequence of warmer oceans.
Even meteorologists who expect only small increases in hurricane strength see today’s storms as threat enough.
“You don’t need to be concerned about climate change 100 years from now; strong hurricanes are a fact of life now.” said Chris Landsea, science and operations officer for the National Hurricane Center in Miami. “If we have a major hurricane hitting there now, that makes a bulls-eye on Houston that’s going to be very problematic.”
The Houston area also is among the most flood-prone in the country. Coastal and flat, with clay soils that don’t readily absorb water, half of Neighboring Galveston County and 15 percent of Houston’s Harris County sit inside areas designated as 100-year flood plains by FEMA, according to research by Texas A&M University’s Center for Sustainable Coasts.
Coastal dredging, destruction of coastal wetlands and erosion of barrier islands narrows the buffer between the land and open water, allowing storms to carry more strength inland.
After staying stable for 2,000 years, global sea levels rose eight inches during the 20th century and satellite data show the rate of increase doubling from 1993 to 2003, according to a 2007 report by the United Nations Intergovernmental Panel on Climate Change. The IPCC researchers expect the trend to accelerate in coming years.
And as the water is rising, the land is sinking.
In the Gulf Coast region of Texas, relative sea level rise, or the increase in water levels compared to shore, is exacerbated by subsidence, or the land sinking as drinking water and oil are sucked from below the earth’s surface. Relative sea levels at Galveston, for example, are predicted to increase more than three times as much as those at Neah Bay, Wash., according to a 2009 report of the U.S. Global Change Research Program.