1812 Louisiana Hurricane - Meteorological History

Meteorological History

On August 12, a tropical disturbance entered the Caribbean Sea to the south of Antigua, believed to have been a strong tropical wave. Moving westward, it developed into a tropical storm by August 15, based on ship observations in the region. That day, it passed to the south of Jamaica and later turned to the northwest. Due to the ongoing War of 1812, there was a British blockade of American ships, which caused a lack of observations in the region. As a result, the storm's track was uncertain, although it is believed that the system entered the Gulf of Mexico by August 18; that day, a ship reported hurricane-force winds. After moving northward, the hurricane turned to the northwest off the coast of Louisiana.

Although meteorologist David Roth assessed the storm as making landfall on August 19 at Isle Dernière to the west of New Orleans, a research paper from the American Meteorological Society estimated that the hurricane moved ashore about 40 mi (60 km) southeast of New Orleans. Modern research suggests the storm was the equivalent of a major hurricane (a Category 3 on the Saffir-Simpson Hurricane Scale), or with winds of at least 115 mph (185 km/h), when it made landfall. It passed just southwest of the city, becoming the closest major hurricane to New Orleans. The wind diameter was average to slightly below-average, and the forward speed was normal. Due to its movement, the hurricane likely maintained much of its strength after making landfall and by the time it affected New Orleans. The hurricane gradually weakened over land, passing near Baton Rouge, Louisiana and Natchez, Mississippi on August 20. Heavy rainfall was reported in eastern Ohio beginning on August 21, potentially from the remnants of the storm merging with a cold front.