2007 Atlantic hurricane season

A crowded but weak season

By raw numbers 2007 looked busy: the archive tracks 17 systems, including two depressions that never earned a name. Energy tells a different story. The season's accumulated cyclone energy of 73.9 was the lowest since 2002, and the National Hurricane Center's season summary placed it at about 84 percent of the 1951 to 2000 median. Eight cyclones lasted two days or less, tying 2005 for the most such short-lived storms.

The weakness came despite La Nina, which usually favours Atlantic hurricanes. An unusually strong upper-level trough over the central Atlantic in September, paired with a persistent ridge over eastern North America from August to October, raised wind shear and encouraged sinking air across much of the basin. Pre-season outlooks had expected an active year: Colorado State University called for 14 named storms and 7 hurricanes, and NOAA for 13 to 17 named storms. Both lowered their numbers as the season went on.

The site's counts match the National Hurricane Center's 15 named storms because they include Andrea, a subtropical storm whose 50-knot winds count toward the season total even though it never became fully tropical. For that reason Andrea's tropical-stage peak is blank in the storm table.

How the season unfolded

Activity began before the official start. Andrea grew from a strong offshore low off the southeastern United States in early May; before it became subtropical, the parent storm's winds and waves pounded the coast and caused six deaths, including the four-person crew of a sailboat lost off North Carolina. Tropical Storm Barry formed near western Cuba on 1 June, the first day of the season, and soaked Cuba and Florida. Tropical Storm Chantal followed at the end of July, a short-lived system north of Bermuda.

August brought the season's first hurricane, Dean, which reached hurricane strength on 16 August and dominated the month. Tropical Storm Erin formed in the Gulf of Mexico at the same time and came ashore in Texas as a depression. Felix formed on 31 August and exploded over the Caribbean in the first days of September.

September was the busiest month but produced mostly brief, modest storms. Gabrielle came ashore on the North Carolina Outer Banks, Humberto sprang up off Texas, Ingrid, Jerry and Melissa faded over open water, Karen became a minimal hurricane far out in the Atlantic, and Lorenzo struck eastern Mexico. After a quiet October, Noel became the season's last hurricane in early November, and Olga formed in December, well after the official end of the season.

Two Category 5 hurricanes

Hurricane Dean was the season's strongest storm. It deepened rapidly in the eastern Caribbean, its winds rising from 80 to 145 knots in 24 hours, then passed south of Hispaniola and Jamaica before regaining Category 5 strength over the northwestern Caribbean. The archive records a peak of 150 knots and a central pressure of 905 hectopascals on 21 August. Dean's landfall pressure ranks third lowest on record in the Atlantic, behind only Hurricane Gilbert of 1988 and the 1935 Labor Day hurricane.

Hurricane Felix was smaller and even quicker to intensify. Its winds climbed from 35 to 150 knots in the 48 hours ending early on 3 September, when its pressure bottomed out at 929 hectopascals. A reconnaissance aircraft met such severe turbulence in the eyewall that it abandoned its mission. An eyewall replacement cycle briefly cut Felix to Category 3, but it regained Category 5 just before landfall.

Rapid strengthening marked the season well beyond the two Category 5 storms. Hurricane Humberto grew from a 25-knot low into an 80-knot hurricane within 24 hours off the upper Texas coast, one of the fastest rates on record for a system starting below tropical storm strength. Lorenzo also became a hurricane less than 12 hours after being named.

Landfalls and impacts

Dean made landfall near Majahual in Mexico's Costa Maya region on 21 August at 150 knots, the first Category 5 landfall in the Atlantic since Hurricane Andrew in 1992. The sparsely populated coast limited the damage, though Majahual lost hundreds of buildings and its cruise port was wrecked. Dean crossed the peninsula and struck mainland Mexico again near Tecolutla as a Category 2 hurricane on 22 August. The National Hurricane Center counts 32 direct deaths, 14 of them in Haiti and 12 in Mexico, all of the Mexican deaths tied to the second landfall. In Martinique, damage was estimated at 400 million euros, with severe losses to banana and sugar cane crops.

Felix came ashore near Punta Gorda, Nicaragua, on 4 September, damaging thousands of structures along the coast north to Puerto Cabezas before flooding rains spread inland over Nicaragua and Honduras. Media reports compiled by the National Hurricane Center put the toll at 130 deaths, with 70 people missing; no monetary damage estimate was available.

The United States escaped major hurricanes. Humberto made landfall near High Island, Texas, on 13 September with 80-knot winds, the first hurricane to strike Texas since 2003; it caused one direct death and property damage of about 50 million US dollars at 2007 prices. Erin's floods were deadlier: the storm and its remnants directly caused 16 deaths in Texas, Oklahoma and Missouri, most of them in inland flooding. Lorenzo came ashore near Tecolutla, almost where Dean had, and caused six deaths in Veracruz and Puebla.

The late season was the deadliest for the Caribbean. Noel dropped several days of torrential rain on Hispaniola and Cuba in late October, with gauges in the Dominican Republic overflowing and totals there possibly approaching 1,000 millimetres. The National Hurricane Center estimates 163 deaths, most from floods and mudslides, with 59 others missing. In December, Olga fell on ground still saturated from Noel, and at least 22 people died in the Dominican Republic, with further deaths in Haiti and Puerto Rico.

Records and legacy

The names Dean, Felix and Noel were retired after the season. The frequent rapid changes in strength also made 2007 a hard year for forecasters: official intensity forecast errors ran well above the previous five-year average, and warnings for Humberto came with only 16 hours of lead time for tropical storm conditions and 2 hours for hurricane conditions because the storm developed so quickly near the coast.