The amount of water Ike has put in motion is about 50% greater than what Katrina did, and thus we can expect Ike’s storm surge damage will be similar to or greater than Katrina’s. The way we can estimate this damage potential is to compute the total energy of Ike’s surface winds (kinetic energy). To do this, we must look at how strong the winds are, and factor in the areal coverage of these winds. Thus, we compute the Integrated Kinetic Energy (IKE) by squaring the velocity of the wind and summing over all regions of the hurricane with tropical storm force winds or higher. This “Integrated Kinetic Energy” was recently proposed by Dr. Mark Powell of NOAA’s Hurricane Research Division as a better measure of the destructive power of a hurricane’s storm surge than the usual Category 1-5 Saffir-Simpson scale. For example, Hurricane Katrina hit Mississippi as a strong Category 3 hurricane, yet its storm surge was more characteristic of a Category 5 storm. Dr. Powell came up with a new scale to rate potential storm surge damage based on IKE (not to be confused with Hurricane Ike!) The new scale ranges from 1-6. Katrina and Wilma at their peaks both earned a 5.1 on this scale. At 9:30am EDT this morning, Ike earned a 5.6 on this scale, the highest kinetic energy of any Atlantic storm in the past 40 years.

In other words, the best case scenario is that Ike continues to confound expectations, remains a surface-level Category 1 hurricane (which it effectively is right now), and hits Texas with a storm surge of the sort that might ordinarily be generated by a Cat 4-5. Or, to be more precise, without the narrow peak a Cat 4-5 would generate just east of its eye, but with an even broader swath of serious flooding. The worst case scenario is that Ike confounds expectations by tying together its upper and lower circulation, its eyewall gets replaced, and it suddenly strengthens into a truly major hurricane – bringing incredibly destructive winds on top of the storm surge.
Listening to the emergency responders in the Houston metro area, I’m struck that they’re largely focused on the potential for the worst-case scenario. That is, they seem to be worried about shifts in the track and the strength of the winds. It’s now virtually certain that Galveston island will be flooded from the bay-side; and it’s not outside the realm of possibility that the surge will exceed the height of the floodwall, too. You’d think that, after Katrina, they might have figured out that the intensity at landfall matters a whole heck of a lot less than the width of the field and the resultant surge. Perhaps Ike will make them pay attention to the IKE.

Boards are going up in the area… just a few now: a Wal-Mart here, a gas station there, one of my neighbors…. ours are going up this afternoon.

Example: I teach a Saturday morning class at the University of Houston. My class is scheduled to start at nine am–two hours after projected landfall. (My classroom, btw, is below ground.) I emailed the Weekend U coordinator last night and asked almost rhetorically, Um, school is cancelled for Saturday, right? Just heard back. No word. She’ll get back to me. The university is still pissed over giving us what amounted to a six-day vacation during Rita, and, damnit, they’re not making that mistake again!

Fortunately, we have a SW to NE flow over the state right now, so I don’t think Ike will stall and rain itself out as that previous storm did. I distinctly remember some places totaled well over 30″ of rain that time, and I’ll never forget the images of submerged semi tractor-trailer rigs on Katy Freeway, a stretch of interstate I’ve driven many, many times.