1900 Galveston hurricane
The Great Galveston hurricane made landfall on September 9, 1900, near Galveston, Texas. It had estimated winds of at landfall, making the cyclone a Category 4 storm on the modern day Saffir–Simpson Hurricane Scale.
The hurricane caused great loss of life, with a death toll of between 6,000 and 12,000 people; the number most cited in official reports is 8,000, giving the storm the third-highest number of deaths or injuries of all Atlantic hurricanes, after the Great Hurricane of 1780 and Hurricane Mitch in 1998. The Galveston Hurricane of 1900 is the deadliest natural disaster to strike the United States. This loss of life can be attributed to the fact that officials for the Weather Bureau in Galveston brushed off the reports because the city had "weathered them all" and they did not realize the threat. The second-deadliest storm to strike the United States, the San Ciriaco hurricane of 1899, caused around 3,400 deaths.
1840–49 Atlantic hurricane seasons
The Great Havana Hurricane of 1846. October 5–15.
In October, a major hurricane, likely a Category 5, moved through the Caribbean Sea. This Great Havana Hurricane struck western Cuba on October 10. was the most intense tropical cyclone in recorded history for 78 years and the first known Category 5-strength hurricane to strike Cuba. Unusual in many aspects, the 1846 Havana hurricane was the most intense of its time. Though atmospheric pressure readings in Cuba reached as low as 916 mbar. Although no reliable wind measurements were available at the time, a separate study also estimated that it produced Category 5-strength winds. In Cuba, the storm caused hundreds of deaths, capsized dozens of ships, obliterated buildings, uprooted trees, and ruined crops. Many towns were wholly destroyed or flattened and never recovered, while others disappeared entirely.
It hit the Florida Keys on October 11, destroying the old Key West lighthouse, the Sand Key Light, and Fort Zachary Taylor. In Key West, widespread destruction was noted, with 40 deaths, many vessels rendered unfit, and widespread structural damage, with all but eight of the 600 houses in Key West damaged or destroyed. Water rose to about 8 feet in lower streets. Few supplies arrived in the following days and relief efforts were gradual, with few resources within the town's vicinity. The hurricane was so destructive that years afterward, greenery on the key was sparse, and little native vegetation existed. Signs of ecological damage remained even in the early 1880s. The hurricane then headed northward, and on October 13 and hit Tampa Bay as a major hurricane. As it approached, it sucked the water out of the bay, causing the Manatee River to be so low that people walked horses across it. The hurricane moved across Florida, and remained inland over Georgia, South Carolina, North Carolina. It moved up the Chesapeake Bay, causing extensive damage through Virginia, Maryland, Washington D.C., and Pennsylvania. Some disputed reports say that at least 600 were killed; however, the official death report from Cuba says 163 deaths and damage throughout the areas it affected. 
October 10–13.
A hurricane hit Tobago on October 11, resulting in 27 casualties.