Ike is larger than Katrina was, both in its radius of tropical storm force winds--275 miles--and in it radius of hurricane force winds--115 miles. For comparison, Katrina's tropical storm and hurricane force winds extended out 230 and 105 miles, respectively. Ike's surge will probably rival the massive storm surge of Hurricane Carla of 1961. Carla was a Category 4 hurricane with 145 mph winds at landfall, and drove a 10 foot or higher storm surge to a 180-mile stretch of
coast. A maximum storm surge of 22 feet was recorded at Port Lavaca, Texas . Despite the fact that the center of Carla hit over 120 miles southwest of Houston, the hurricane drove a 15-foot storm surge into the bays along the south side of the city. Ike's maximum surge is not likely to reach the extreme values above 20 feet seen in Hurricane Carla, though. Texas
Then he tells us about the surge:
Ike will probably inundate a 250-mile stretch of Texas coast from Port O'Connor to the Louisiana border with a 10-15 foot storm surge. This will occur even if Ike is a Category 1 storm at landfall. If Ike is a Category 3+ hurricane at landfall, surges of 20+ feet are possible. The latest experimental storm surge forecast From NOAA's SLOSH model (Figure 1) shows a 10% chance that Ike's storm surge will exceed 18-21 feet at Galveston. The Galveston sea wall is 17 feet high, so it may get overtopped. At noon today, a mandatory evacuation of the entire island was ordered in case this worst-case scenario is realized. The official NHC forecast is calling for maximum storm surge heights of 20 feet.
Here is the damage:
We must assume Ike will intensify to a Category 3 hurricane by landfall, which would likely do $20-$30 billion in damage. Ike's storm surge is going to be affect a huge area and be tremendously destructive.