High Quality Content by WIKIPEDIA articles! Hurricane Betsy was a Category 4 hurricane of the 1965 Atlantic hurricane season which caused enormous damage in the Bahamas, Florida, and Louisiana. Betsy made its most intense landfall near the mouth of the Mississippi River, causing significant flooding of the waters of Lake Pontchartrain into New Orleans. As it is mistakenly known as first hurricane to cause over a billion dollars in damage (1965 dollars, not adjusted for inflation), it earned the nickname "Billion-Dollar Betsy".