FORT LAUDERDALE, Fla. – When the 2010 hurricane season ends Tuesday, it will be remembered as one of the busiest and most merciful on record.

Almost from the start, it bustled with activity, producing 19 named storms and setting records, including the fastest formation of four Category 4 hurricanes. In total, 12 hurricanes emerged, yet not one struck the U.S. shoreline, marking the first time that the nation escaped unscathed when that many hurricanes arose.

Only one anemic system, Tropical Storm Bonnie, stumbled ashore in July.

“It’s just unheard of to have this many hurricanes and not have any hit the United States,” said Max Mayfield, former director of the National Hurricane Center in Miami-Dade County.

Before the start of the season, experts predicted that 2010 would be extremely busy. They cited record warm waters in the tropics, light winds and the arrival of La Nina, the atmospheric force that promotes hurricane formation.

Yet thanks largely to an expansive dome of high pressure settling over the eastern Atlantic, numerous storms were guided north into the Atlantic before they reached the East Coast.

Among them were hurricanes Danielle, Earl, Igor, Julia, Lisa, Otto and Shary. Earl came closest, passing about 80 miles east of North Carolina’s Outer Banks in early September.

Whether the high pressure, called the Bermuda High, will remain in the same place next season is unknown but unlikely, forecasters said.