Hurricane Katrina

Post Landfall 3 | Summary
Posting Date: August 28, 2005, 11:45:00 AM

Hurricane Katrina continues to both strengthen and grow larger. As of 5:00 a.m. EDT, Sunday, August 28, Katrina is a Category 4 hurricane with maximum sustained winds of 145 mph and a minimum central pressure of 935 mb. The National Hurricane Center (NHC) is forecasting some further strengthening over the next 24 hours, though there is also some possibility that Katrina will go through another cycle of eyewall replacement, increasing the uncertainty regarding intensity at the time of landfall. Hurricane force winds currently extend outward up to 85 miles from the center of the storm. Tropical storm winds extend outward up to 185 miles. This makes Katrina a very large hurricane. A hurricane warning is in effect for the north central Gulf coast from Morgan City, Louisiana east to the Alabama/Florida border. Mandatory evacuation orders have been issued for Grand Isle, Louisiana’s only inhabited barrier island, and voluntary evacuations have been called for in other coastal parishes. Further mandatory evacuation orders may be issued today. Hurricane Katrina took a more westerly track than was expected after leaving the Florida peninsula in the early morning hours of Friday, August 26. The storm is currently moving to the west-northwest at 10 mph. A gradual turn toward the northwest is expected later today. According to the NHC’s most likely track (see map below), this takes Katrina almost directly over the low-lying city of New Orleans sometime tomorrow. Coastal storm surge of 15 to 20 feet above normal tide levels could have a significant impact. The forecast track and intensity of Hurricane Katrina is reminiscent of two major historical events: Hurricane Betsy in 1965 and Hurricane Camille in 1969. Both came ashore in similar locations, south of New Orleans. Betsy, a Category 4 hurricane at landfall in Louisiana, then took a northwesterly path, keeping both New Orleans and Baton Rouge just to the right of the storm’s path, where the strongest winds are felt. More than seventy people lost their lives. Hurricane Camille, the more deadly of the two storms with more than 250 fatalities, maintained a more northerly path after landfall skirting New Orleans and Baton Rouge to the right. AIR estimates that both storms, were they to recur today – given current property exposures and current prices – would cost the insurance industry in excess of $10 billion. Last Thursday, August 25, Hurricane Katrina arrived along the heavily populated stretch of coast between Hallandale Beach and North Miami Beach as a weak Category 1 hurricane. However, the high density and value of properties in Miami-Dade County, as well as the storm’s slow forward speed at landfall (6mph), will contribute to higher insured losses in Florida than one would normally expect for a typical weak Category 1 storm. Mobile homes in Davie, Dania Beach and Pembroke Park sustained significant damage to mobile homes, and damage to roof coverings has been reported from Fort Lauderdale to the middle and upper Keys. Katrina also dumped heavy rain across South Florida. Up to 18 inches in some locations of Miami-Dade caused significant street flooding, while the combination of saturated soils and prolonged winds caused large numbers of downed trees. (Please see Fridays’s ALERT posting for AIR’s estimated insured losses for Katrina’s first landfall.) The AIR tropical cyclone team has run scenarios using the latest information about the storm’s current and forecast meteorological parameters, as well as its forecast track. Eleven of these are now posted on the Scenarios page of this website. Also included on the Scenarios page is AIR’s probability of loss exceedance curve for the industry. Because Katrina’s second landfall is expected more than 72 hours after the first landfall in Florida, AIR is providing two sets of event sets for Hurricane Katrina. One is for Katrina’s combined losses from the two landfalls, the second is for Gulf losses (second landfall) only. These are being provided together in zipped files for CATRADER and CLASIC/2. Upon unzipping, users will be able to access the two files, which are clearly labeled. Both “All” and “Select” event sets are provided. The “All” event sets contains hundreds of scenarios simulated for this event and are therefore the most appropriate method for estimating your potential losses. Sets of 11 specific scenarios, which are selected from the full event sets and represent the range of potential losses across the full industry loss distribution, are available under the “Select” event sets. AIR continues to monitor powerful Hurricane Katrina closely and will update the loss estimates tomorrow.

Post Landfall 3 | Downloads
Posting Date: August 28, 2005, 11:45:00 AM