This article encompasses the 1840–1849 Atlantic hurricane seasons. While data is not available for every storm that occurred, some parts of the coastline were populated enough to give data of hurricane occurrences. Each season was an ongoing event in the annual cycle of tropical cyclone formation in the Atlantic basin. Most tropical cyclone formation occurs between June 1 and November 30.
The 1821 Norfolk and Long Island Hurricane was one of four known tropical cyclones that have made landfall in New York City. Another, even more intense hurricane in the pre-Columbian era left evidence that was detected in South Jersey by paleotempestological research. The third was the 1893 New York hurricane, and the fourth was Hurricane Irene in 2011.
Tropical Storm Matthew was a weak tropical storm in the 2004 Atlantic hurricane season that made landfall on Louisiana. It was the thirteenth tropical storm of the season and the ninth to affect the United States. It formed over the western Gulf of Mexico on October 8 and struck south-central Louisiana two days later. The combination of the storm and an upper cyclone over the southern Plains brought heavy rains to much of the Gulf Coast, with the highest amounts reported over 15 inches (380 mm) in northern Louisiana. Damage was minimal, totaling $305,000 (2004 USD), and no casualties were reported.
The 1851 Atlantic hurricane season was the first Atlantic hurricane season to be included in the official Atlantic tropical cyclone record. Six known tropical cyclones occurred during the season, the earliest of which formed on June 25 and the latest of which dissipated on October 19. These dates fall within the range of most Atlantic tropical cyclone activity. None of the cyclones existed simultaneously with another. Three of the six storms only have a single point in their track known.
The 1852 Atlantic hurricane season was one of only three Atlantic hurricane seasons in which every known tropical cyclone attained hurricane status. Five tropical cyclones were reported during the season, which lasted from late August through the middle of October; these dates fall within the range of most Atlantic tropical cyclone activity, and none of the cyclones coexisted with another. Though there were officially five tropical cyclones in the season, hurricane scholar Michael Chenoweth assessed two of the cyclones as being the same storm. There may have been other unconfirmed tropical cyclones during the season, as meteorologist Christopher Landsea estimated that up to six storms were missed each year from the official database; this estimate was due to small tropical cyclone size, sparse ship reports, and relatively unpopulated coastlines.
The effects of Hurricane Katrina in Florida were in both the southern portion of the state and in the panhandle. After developing on August 23, Katrina made landfall near the border of Broward and Miami-Dade counties with 80 mph (130 km/h) winds on August 25. While it was crossing the state, the hurricane's convection was asymmetrical, primarily located to the south and east of the center. As a result, high rainfall totals occurred in the Miami area, peaking at 16.43 in (417 mm) in Perrine. The rains caused flooding, and the combination of rains and winds downed trees and power lines, leaving 1.45 million people without power. Damage in South Florida was estimated at $523 million (2005 USD), mostly as a result of crop damage. Further south, the hurricane spawned a tornado in the Florida Keys. In the island chain, Katrina caused heavy rainfall and gusty winds.
The 1865 Atlantic hurricane season included two landfalling hurricanes, with one that caused over 325 deaths. The first storm was reported on May 30 by ships in the western Caribbean. A month later, a storm hit southern Texas, and in late August, a storm paralleled the coastline of the Carolinas. The fourth storm of the season was also the longest-lasting, forming east of the Lesser Antilles before hitting Guadeloupe and eventually moving ashore in Louisiana. In both of its major landfalls, the storm left many houses destroyed. There was confusion whether or not the fifth storm of the season was separate from the fourth storm, as both systems struck Louisiana in September. Another hurricane occurred in late September, before the final storm of the season developed north of Panama. The final hurricane struck Cuba and Key West, Florida before dissipating north of Bermuda on October 25.
The 1850 Atlantic hurricane season was the last season excluded from the scope of the official Atlantic hurricane database. Although meteorological records are sparse and generally incomplete, they indicate that three significant tropical cyclones affected land, each causing some degree of damage. The first system struck North Carolina on July 18, causing significant damage before battering the Mid-Atlantic states with high tides, strong winds, and heavy rainfall. Torrential rainfall caused river flooding from Baltimore to Philadelphia, particularly along the Schuylkill River, which took the lives of 20 people in various incidents. Strong winds damaged property and public facilities in and around New York City, and damaging floods extended into central and northern New England. Crops and railroad infrastructure suffered throughout the entire region.
