Records of Northeast Florida storms began in 1885, and since then Jacksonville Beach has had relatively mild hurricane activity compared to many coastal areas, though Hurricane Dora made landfall just south of Jacksonville Beach in 1964 and caused significant damage, Hurricane Floyd came close to the Jacksonville Beaches in 1999, and Hurricane Matthew came even closer in 2016. Hurricanes can bring high waves, erosion, heavy rain, flooding, and wind, with damage including eroded sand dunes, flooded homes and businesses, washed-out roads, wind damage to homes, businesses, and property, downed power lines, lost utility services, and tree debris; Floyd and Matthew both caused substantial damage to the Jacksonville Beach Pier. Nor'easters are a different kind of storm, a large storm front with strong, steady winds from the northeast that can last several days and cause flooding and beach erosion, and they affect Jacksonville Beach much more frequently than hurricanes, almost every year. One major nor'easter during Thanksgiving 1984 caused severe beach and dune erosion, some flooding, and destroyed part of the St. Johns County Pier while it was under construction. Hurricanes are tropical cyclones that form in warm tropical waters and can quickly grow into huge storms that travel long distances before dissipating; radar shows them as spinning masses of clouds with a calm, clear eye at the center, usually 20 to 40 miles across, surrounded by a wall of thick clouds and the storm's strongest winds, and they are often about 300 miles wide. A storm is called a hurricane when its winds reach 74 miles per hour, while storms with average winds from 39 to 73 miles per hour are tropical storms and a tropical depression has average winds of 38 miles per hour or less. Hurricane strength is rated on the Saffir-Simpson Scale from Category 1 through 5, with Category 1 at 74 to 95 miles per hour, Category 2 at 96 to 110, Category 3 at 111 to 130, Category 4 at 131 to 155, and Category 5 above 155 miles per hour, and special planes from the National Hurricane Center in Miami fly into hurricanes to measure wind power.