1997 Atlantic hurricane season

An El Niño year after two busy seasons

Activity dropped sharply after 1995 and 1996. The National Hurricane Center's season summary counted seven tropical storms, three of which became hurricanes, plus one subtropical storm, against long-term averages of ten storms and six hurricanes. The site's archive gives 8 tropical storms because it counts any storm with one-minute winds of 34 kt or more, including the June subtropical storm. Three storms reached hurricane strength and one, Erika, became a major hurricane. Accumulated cyclone energy came to 40.9.

The NHC tied the quiet year to the El Niño then under way. El Niño years often bring stronger westerly winds at upper levels over the tropical Atlantic, which shear the tops off developing thunderstorms. In September 1997 those westerlies covered most of the tropical wave track, and Erika was the only cyclone to form that month. August stayed empty even though upper winds between Africa and the Lesser Antilles were near normal. The same El Niño boosted the eastern and western Pacific seasons.

All but one of the year's cyclones formed between 22°N and 32°N in the western Atlantic, most from frontal boundaries or upper-level lows, and tropical waves led directly to only two named storms. The storms met strong shear and cool water within a few days, so most were short and weak.

Short-lived storms off the East Coast

The first system went unrecognized in real time. Forecasters treated it as an extratropical low, but a post-season review found a mostly subtropical structure and added a subtropical storm that formed north of the Bahamas on 1 June, reached 45 kt the same day and merged with a front south of New England on 2 June. Tropical Storm Ana formed from a frontal low off South Carolina on 30 June and turned extratropical over cool water on 4 July.

Hurricane Bill grew from an upper-level low northeast of Puerto Rico, passed about 150 nautical miles northwest of Bermuda on 11 July and reached its 65 kt peak the next day before a front absorbed it. The same front spun up Tropical Storm Claudette south-southeast of Cape Hatteras on 13 July. On 14 July the NOAA G-IV jet flew its first operational mission around a tropical cyclone, dropping GPS sondes into Claudette's surroundings.

Hurricane Danny stalls over Mobile Bay

Hurricane Danny formed south of Louisiana on 16 July, became a hurricane early on 18 July and made its first landfall near Empire and Buras, Louisiana, the same morning. It was a small hurricane, with maximum winds only 8 to 9 nautical miles from the center. Danny moved slowly east-northeast, an unusual path for a July storm in the Gulf, and reached its peak of 70 kt and 984 mb south of the Mississippi coast. Its eye reached the mouth of Mobile Bay before dawn on 19 July, and the center crossed the bay's southeastern shore near Mullet Point around midday. Dauphin Island recorded sustained hurricane-force winds.

Because Danny barely moved, its rain piled up over southern Alabama. The Dauphin Island Sea Lab measured 932.4 mm, one of the largest hurricane rainfall totals recorded in the United States, including a state 24-hour record of 826.0 mm, and radar estimates reached around 1,100 mm nearby. Most of the heaviest rain fell near the coast or over water. Danny later crossed the Carolinas, strengthened again off Virginia and passed about 25 nautical miles southeast of Nantucket on 26 July.

The NHC counted five direct deaths from Danny: a sailor off Fort Morgan, a woman killed by a tornado in Lexington County, South Carolina, and three flood drownings in Charlotte, North Carolina. It listed five more indirect deaths, four of them in traffic accidents in Georgia. Insured losses came to about $60 million, and the NHC estimated total damage at around $100 million in 1997 dollars. Other totals give nine deaths for the storm.

Erika and a quiet autumn

Hurricane Erika formed about 1,000 nautical miles east of the Lesser Antilles on 3 September, the only storm of the year to come from the deep tropics. It passed within about 75 nautical miles of the northeasternmost Leeward Islands on 5 to 8 September, just far enough away that hurricane conditions missed them. Erika reached its peak of 110 kt and 946 mb on 8 September about 300 nautical miles north of the islands, the season's strongest wind and lowest pressure. It then passed east of Bermuda and brought storm-force gusts to the Azores on 15 September.

Waves from Erika caused minor damage across the northeastern Caribbean, and two surfers died off northern and eastern Puerto Rico, the season's only deaths outside Danny in the NHC count. Southwesterly winds around the storm carried ash from the Montserrat volcano over Antigua. Dropsondes released in the eyewall on 8 September measured 128 kt only 40 m above the sea.

October brought two weak storms. Tropical Storm Fabian formed from a wave that crossed Puerto Rico and stayed at sea, and Tropical Storm Grace spun up along a frontal trough north of Hispaniola on 16 October and faded the next day. Forecast verification that year rested almost entirely on Erika: it produced 37 of the 38 three-day track forecasts the NHC verified.