Hurricane Karl

Post Landfall 3 | Summary
Posting Date: September 17, 2010, 1:30:00 PM

Hurricane Karl made landfall today at 11:30 AM CDT (12:30 PM EST) about ten miles north of the port city of Veracruz (population 444,438 as of 2005). The storm’s Category 3 hurricane-force winds toppled billboards, power poles and trees and prompted the shutdown of oil platforms in the western Gulf of Mexico, including 14 production wells belonging to Petroleos Mexicanos. Mexico’s only nuclear power plant, the Laguna Verde Nuclear Power Plant in Alto Lucero was also shut down. Karl’s maximum sustained winds at landfall were 115 miles per hour, down slightly from 120 mph earlier this morning. It was the strongest storm to strike the region since Hurricane Janet in 1955. According to the National Hurricane Center’s (NHC) 4 pm CDT advisory today, Karl is currently 25 miles west southwest of the port city of Veracruz, tracking westsouthwest at 9 miles per hour. Maximum sustained winds have weakened to 90 miles per hour, making Karl a Category 1 hurricane on the Saffir Simpson Wind Scale. Fortunately, Karl remains a small, tightly wound storm; hurricane force winds extend outward to just 15 miles. Also fortunate is the fact that the storm made landfall to the north of Veracruz, which puts the affected concentration of exposure on the storm’s weaker, left-hand side. Nearer the landfall location, however, homes and businesses in the towns of Cardel are likely to have sustained more significant damage to roofs, windows and cladding. According to reports, some 20 homes have been cut off by flooding. Most insured residential structures in Mexico are made of confined masonry, which performs better than plain masonry under lateral wind loads because of its use of bond beams and columns. However, a large percentage of houses built every year in Mexico are constructed without a building permit, perhaps as large as 50%.In the capital, where there are many commercial buildings, these structures are primarily of masonry or concrete construction. As Karl tracks inland today, it will continue to weaken over the mountainous terrain, though it may still be at hurricane strength when it reaches the state capital of Jalapa (Xalapa), some 60 miles from the coast. In addition to strong and gusty winds, the storm represents a significant threat in terms of torrential rains; Karl is expected to produce total rainfall accumulations of 5 to 10 inches across the central and southern Mexican Gulf Coast. These rains could persist well inland, but not before causing significant flooding in the mountains in Veracruz. In 1999, a storm in the mountains there killed more than 300 people, the majority of whom died in landslides. Today, 15 inches of rain are possible in isolated mountainous locations. Officials are releasing water from reservoirs in advance. Whether heavy rainfall will persist until the remnants of Karl arrive in the Mexico City area is uncertain. Flooding from Karl will exacerbate the flooding southern Veracruz has experienced in the past month, since August 19th. The head of Veracruz weather services called the notably wet period the most significant flood event in 30 years. One million people have been affected. Karl marks the first major hurricane (Category 3 or higher) in recorded history to track through the Bay of Campeche. In 1955 and 1951, respectively, Hurricane Hilda and Hurricane Charley—two other major hurricanes—tracked along the northern edge of this bay, but Karl’s track is much farther to the south. Three other strong storms have impacted the region. The most recent of these was Diana in 1990, with 100 mph winds (Category 2 strength). Today’s landfall is Karl’s second in Mexico. On Wednesday morning, the storm came ashore on Mexico's Yucatan Peninsula about 30 miles east-northeast of Chetumal, the capital of the state of Quintana Roo, with tropical storm strength winds of 65 miles per hour. Hundreds of people were evacuated from the sparsely-populated southern coast. The storm then crossed the Yucatan peninsula Wednesday and emerged into the Bay of Campeche Thursday morning, much weakened but relatively intact. Conditions in the Bay of Campeche were ideal for Karl to reintensify: vertical wind shear was low and sea surface temperatures were about 84-86° Fahrenheit. Karl strengthened rapidly from Category 1 to Category 3 status overnight last night, reaching the Mexican coast slightly faster today than forecasts had predicted. Hurricane Karl is the 11th named storm and the fifth major hurricane of this now very active hurricane season. With its rise to hurricane status, it puts this season ahead of the busy hurricane seasons of 2004 and 2005 in terms of the number of major hurricanes so early in the year. The AIR tropical cyclone team is gathering the available meteorological information on Karl and has begun running simulations of the storm in the AIR Tropical Cyclone Model for Mexico. Results will be made available after the storm has completed its track inland.

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Posting Date: September 17, 2010, 1:30:00 PM