(1 p.m.EST) -- We're finished. The 2011 Atlantic hurricane season officially ended yesterday -- and, as predicted, it was an active season, with storms diverting scores of cruise ships and keeping numerous Caribbean ports on the defensive.
The season, which spanned six months, matched 2010 for named storms: 19 in all (winds of 39 miles per hour or more), with seven becoming hurricanes (74 miles per hour plus) and three becoming major storms (111 miles per hour plus). According to the National Oceanic and Atmospheric Association (NOAA), 19 tropical storms represent the third-highest total -- tied with 1887, 1995 and last year -- since records began in 1851. However, the number of hurricanes and major hurricanes was only slightly above the average of six and two, respectively.
During the quieter Eastern Pacific season, which runs from May 15 to November 30, there were 11 named storms total, with 10 hurricanes and 6 major storms.
Through it all, we kept the Hurricane Zone updated with up-to-the-minute itinerary changes, port closures and weather advisories.
How active was the hurricane season? In its pre-season report issued in May, NOAA's Climate Prediction Center called for an above-normal season with 12 to 18 named storms, of which 6 to 10 could become hurricanes. Of the hurricanes, three to six were predicted to become major storms. During an August revisal, NOAA officials upped the initial prognostications to 14 to 19 named storms, with 7 to 10 becoming hurricanes and 3 to 5 become major storms. The actual tallies fell within the updated range.
A number of factors may have contributed to the active season, says NOAA. These include exceptionally warm Atlantic Ocean temperatures (the third warmest on record) and the possible redevelopment of La Niña, a Pacific-based phenomenon that can lower wind shear in the Atlantic. Higher vertical wind shear can contribute to suppressing the creation of storms.
The Atlantic storm that'll be long remembered by cruisers (and East Coasters) is Irene, which disrupted more than 20 itineraries, damaged cruise line private islands as it raged through the Bahamas, and sparked a hurricane-sized PR controversy after the port authority of San Juan ordered a pair of ships to leave early -- without hundreds of booked passengers. Irene was also the lone hurricane to hit the United States in 2011, and the first one to do so since Ike struck southeast Texas in 2008, severely damaging the popular turn-around port of Galveston.
There were other game-changers, too. In October, Rina sent more than a dozen ships fleeing from Mexico's Yucatan ports.
What about the activity in the Pacific? Historically, when the Atlantic experiences above-average activity, the Pacific experiences below-normal activity (and vice versa). The results were in line with this inverse proportionality. NOAA predicted 9 to 15 named storms, with four to eight hurricanes. The 10 named storms fell within the range, but more storms than anticipated became hurricanes. Still, with only a handful of ships cruising Mexico's west coast during the summer months, hurricanes don't have the industry-wide impact they do in the Caribbean. The biggest disruptor, Jova, a powerful cyclone that peaked as a major storm with winds of 125 miles per hour, scattered HAL, Carnival and Disney Cruise Line ships stationed in the region.
Relive the Atlantic season in this video courtesy of NOAA. The Atlantic's first named storm, Arlene, appears just south of Cuba 45 seconds in. (Irene makes an appearance just after minute two.)