New Orleans has ordered a mandatory evacuation of all 485,000 residents, as Katrina, now a Category 5 hurricane, heads towards the city for a possible dead-on strike, with the storm surge devastatingly timed to hit at high tide. The city, which sits in a soggy bowl an average 6 feet below sea-level, will likely see flood waters overwhelm levees even if it escapes a direct hit. The storm surge could reach 28 feet, topped by 30-foot waves in some locations.
This could be the dreaded “500-year storm” that meteorologists have long feared, and which no levee system could possibly handle. In addition to the storm surge, Katrina currently packs sustained winds of up to 175 mph, and could drop over 15 inches of rain on the city as it passes through.
As we sit and watch and hope that New Orleans once again dodges a bullet, a couple thoughts come to mind. The first is the practical concern of how Louisiana will effectively deal with the aftermath of the hurricane, what with so many of its National Guard units currently fighting and dying in the streets of Iraq?
My second thought is a cautionary one, and selfishly strikes much closer to home. I have been constantly amazed during the ongoing debate over replacing the Alaska Way Viaduct, by those who assert that the earthquake risk has been over-blown. While Seattle has never in its brief history experienced the type of catastrophic quakes seen elsewhere, the seismologic record makes it clear that it has in the past, and most definitely will again in the future. Perhaps both Seattle and New Orleans will be spared their disaster for another 150 years… or perhaps it will strike tomorrow. And if it does, the Viaduct might not just pancake, but rather topple over onto the waterfront as the soil beneath it liquifies and the aging seawall collapses.
A major earthquake will strike. We cannot avoid it, nor accurately predict its timing. But like New Orleans, we can attempt to be prepared.
Katrina is still strengthening, and tracking towards landfall just east of New Orleans, with gusts up to 200 mph. This hurricane is not just powerful, but extremely large, and could end up being the most powerful storm in recorded history… so powerful, that it is pushing the limits of existing models. If you know anybody in and around N.O. planning to ride out the storm, urge them to get out NOW!