Hurricane Dean

Landfall | Summary
Posting Date: August 21, 2007, 2:30:00 PM

Category 5 Hurricane Dean pummeled the east coast of the Yucatan Peninsula with 165-mph winds and driving rain early this morning. It was the most intense Atlantic hurricane to make landfall in two decades and the first landfalling Category 5 since Hurricane Andrew in 1992. The eye of the storm came ashore at about 3:30 AM local time along a sparsely populated stretch of the Mexican coast near the tourist resort of Majahual, about 40 miles northeast of the state capital Chetumal. Dean's strongest winds, which occurred to the north of the landfall point, battered an uninhabited 70-mile stretch of coast belonging to the Ka'an Biosphere Reserve. As Dean made its way inland, the center passed about 15 miles north of Chetumal, which has a population near 150,000. Hurricane-force winds in Chetumal broke tree limbs and left electrical cables crisscrossing the streets—some of which were flooded with ankle-deep water. The city remains without power. As a result of its previous experience with devastating hurricanes, Chetumal largely abandoned woodframe construction and is today dominated by concrete. Tin roofs, however, were ripped from structures, adding to the windborne debris that shattered windows throughout the city. Smaller towns in the affected area, with poorer construction, will fare worse. Dean weakened on its passage across the Yucatan peninsula, and as of 1:00 PM CDT is a Category 1 storm with maximum sustained winds of 85 mph. The center is located about 45 miles south-southeast of Campeche. Dean is expected to continue its west-northwestward track and reemerge into the Bay of Campeche, where the state oil company has evacuated oil rigs in preparation. On Monday night, in advance of the storm, the army evacuated fishing villages and seaside resorts all along the Yucatan coast, taking tourists and residents to schools and hotels farther inland. Mexican authorities said about two-thirds of the 60,000 vacationers in the Cancun area had fled, though ultimately the resort city experienced only tropical storm force winds. The government had also evacuated Caye Caulker and Ambergris Caye, two popular U.S. tourist destinations. In 1955, Chetumal was battered by another powerful Category 5 storm: Hurricane Janet. Janet crossed the Yucatan on a remarkably similar path to Hurricane Dean, reemerging in the Gulf weakened, but still at hurricane force. Using the available meteorological parameters and forecast track for Dean, the AIR tropical cyclone team has run AIR's Mexico hurricane model, which is due to be released later this year. AIR estimates that insured wind and flood losses to onshore properties in Mexico from Hurricane Dean are unlikely to exceed $400 million. AIR estimates that the percentage of residential structures that are insured is low in this region. Commercial take-up rates, however, are much higher and these will ultimately drive the insured losses from this event. AIR additionally estimates that approximately 20% of the insured loss will result from flooding. It is interesting to note that flood damage from Hurricane Janet (1955) was significantly higher than is expected for Dean. Two tropical storms that struck the Yucatan prior to Janet's arrival had led to already highly saturated soils. As always, it is important to note that there is still considerable uncertainty with respect to where Dean will make a second landfall along Mexico's central coast and at what intensity. Additional uncertainty exists with respect to how much rainfall Mexico City will receive. Forecasters expect that Dean will survive the crossing of the Yucatan and reemerge as a Category 2 storm. It then enters the very warm waters of the southern Gulf. While some restrengthening is possible, there will be little time before the storm makes a second landfall, which is currently forecast to be near Poza Rica, in the Mexican state of Veracruz. Dean is forecast to finally dissipate in the mountains about 100 miles north of Mexico City, and it could bring heavy rains to the Mexican capital.

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Posting Date: August 21, 2007, 2:30:00 PM