Hurricane Betsy was a Category 4 hurricane of the 1965 Atlantic hurricane season

1965 Atlantic hurricane season

The 1965 Atlantic hurricane season officially began on June 1, 1965, and lasted until November 30, 1965. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin....

 which caused enormous damage in the Bahamas, Florida

Florida

Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, and Louisiana

Louisiana

Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...

. Betsy made its most intense landfall near the mouth of the Mississippi River

Mississippi River

The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...

, causing significant flooding of the waters of Lake Pontchartrain

Lake Pontchartrain

Lake Pontchartrain is a brackish estuary located in southeastern Louisiana. It is the second-largest inland saltwater body of water in the United States, after the Great Salt Lake in Utah, and the largest lake in Louisiana. As an estuary, Pontchartrain is not a true lake.It covers an area of with...

 into New Orleans. As it was mistakenly known as the first hurricane to cause over a billion dollars in damage (1965 dollars, not adjusted for inflation), it earned the nickname "Billion-Dollar Betsy".
Betsy formed east of Daytona Beach, Florida

Daytona Beach, Florida

Daytona Beach is a city in Volusia County, Florida, USA. According to 2008 U.S. Census Bureau estimates, the city has a population of 64,211. Daytona Beach is a principal city of the Deltona – Daytona Beach – Ormond Beach, Florida Metropolitan Statistical Area, which the census bureau estimated had...

, and seemed to be on its way to hit the Carolinas, it turned back toward the southwest (making a second complete loop), passing over the Bahamas where winds on Great Abaco Island reached 147 mph (237 km/h).