The 2008 Atlantic basin hurricane season ended with a whimper yesterday, but not before it wreaked havoc across the Caribbean and along the Gulf Coast of the United States.
This year, the hurricane forecast experts just about pegged the busy season they predicted.
In the end, the hurricane season saw 17 tropical depressions form, 16 of which became named storms. Eight of those named storms became hurricanes and five of the hurricanes became major hurricanes of category 3 or higher.
At the beginning of the hurricane season in June, Colorado State University scientists Philip Klozbach and William Gray predicted 15 named storms, eight hurricanes and two major hurricanes. In early August, the pair upped their prediction to 17 named storms, nine hurricanes and five major hurricanes.
This year the National Oceanic and Atmospheric Administration in US issued their annual prediction in a range form. In May, they predicted 12 to 16 named storms, six to nine hurricanes and two to five major hurricanes. The actual numbers all came within those ranges, although at the upper end. In early August, NOAA increased those ranges to 14 to 18 named storms, seven to 10 hurricanes and three to six major hurricanes. Again, the actual figures fell within all three of those ranges.
This year’s tropical cyclones caused extensive damage in several places, notably Cayman Brac and Little Cayman; the Turks and Caicos Islands; Cuba; Haiti; and the Gulf Coast area of the United States.
Hurricane Ike, which devastated the Turks and Caicos Islands, Haiti and Cuba in the Caribbean, also became the third-most destructive hurricane in United States history, causing some $27 billion of damage. The remnants of that storm raced up to the Ohio Valley, bringing hurricane-force gusts as far north as Indiana, Ohio and Pennsylvania.
Ike killed 164 people, including 82 in the United States. More than 200 people remain missing, possibly swept out to sea as they tried to weather the storm in their homes along the Texas Gulf Coast.
The Cayman Islands felt effects from four of the named storms this year. Although Hurricane Dolly did not form into a tropical cyclone until after it had passed west of Grand Cayman in July, the storm brought more than seven inches of rain over a two-day period, causing flooding of low-lying areas.
In late August, Hurricane Gustav appeared headed directly at Grand Cayman as a major hurricane before it turned to the north closer to the Sister Islands. The storm came within 12 miles of Little Cayman brining maximum sustained winds of 82mph and more than six inches of rain. Gustav caused some damage to homes and electricity supply in the Sister Islands, but the damage was considered minor overall.
Hurricane Ike did not end up impacting the Cayman Islands very much when it passed to the north on 8 September, but it came close enough to cause the Cayman Islands Government to issue a tropical storm warning for Cayman Brac and Little Cayman and a tropical storm watch for Grand Cayman.
Hurricanes Gustav and Ike both devastated parts of Cuba, particularly the Isle of Pines, where many people with close heritage links to Caymanians live. The damage to the Isle of Pines resulted in a substantial relief effort organised by Caymanians. As part of the relief effort the Cayman Islands Government sent to the Isle of Pines some of the mobile home trailers that had been shipped to Grand Cayman to provide temporary housing after 2004’s Hurricane Ivan.
When considering the 2008 hurricane season, Caymanians will remember Hurricane Paloma most. The late-season storm formed southwest of the Cayman Islands and appeared to be heading for direct hit on Grand Cayman on 7 November.
However, the storm shifted course slightly at the last minute, taking it about 30 miles east of Grand Cayman and causing only minimal damage. Still, Grand Cayman received more than 13 inches of rain from Paloma.
The eastward shift in course took Paloma on a collision course with the Sister Islands and it devastated Cayman Brac on the 76th anniversary of the deadly hurricane of 1932.
Although no deaths were caused in Cayman Brac by Paloma, the hurricane damaged an estimated 90 per cent of the buildings there. The recovery effort is expected to continue well into 2009.
The Atlantic basin is currently in a multi-decadal upper atmospheric weather phase that supports increased tropical activity. However, other factors such as sea surface temperatures in the Atlantic, Caribbean and Gulf of Mexico and dust storms coming of the coast of Africa can either hinder or aid hurricane development.
Another factor that affects the amount of hurricane-inhibiting wind shear over the Atlantic basin is the El Niño/La Niña phenomenon – also known as ENSO – which is related to sea-surface temperatures in the Pacific Ocean near the equator. Scientists have discovered that El Niño events, which are caused by higher than normal sea surface temperatures, tend to inhibit the formation of tropical cyclones in the Atlantic basin, while La Niña events or neutral ENSO conditions tend to support an active hurricane season in the Atlantic basin.
Based on climatology computer modelling through November, it is currently predicted that the neutral ENSO conditions that were present this hurricane season will continue at least for the first half of 2009. At least one model predicts a La Niña condition to occur in the latter half of 2009.