Tropical Storm Dorothy (1970)

Tropical Storm Dorothy

Tropical storm (SSHWS/NWS)
Satellite image of the storm east of the Lesser Antilles
Formed	August 17, 1970
Dissipated	August 23, 1970
Highest winds	1-minute sustained: 70 mph (110 km/h)
Lowest pressure	996 mbar (hPa); 29.41 inHg
Fatalities	Up to 51 direct
Damage	$34 million (1970 USD)
Areas affected	Lesser Antilles (Martinique landfall)
Part of the 1970 Atlantic hurricane season

Tropical Storm Dorothy was the deadliest tropical cyclone of the 1970 Atlantic hurricane season. The fourth named storm and fifth tropical storm or hurricane of the season, Dorothy developed on August 17 from a tropical wave to the east of the Lesser Antilles. It tracked west-northwestward throughout its entire duration, and despite forecasts of attaining hurricane status, Dorothy reached peak winds of 70 mph (110 km/) – slightly below hurricane status. The storm struck Martinique on August 20, and subsequently began a gradual weakening trend in the Caribbean Sea. On August 23, Dorothy dissipated south of Hispaniola.

Most significantly affected by the storm was Martinique, which received 26.8 in (680 mm) of rainfall in a 24‑hour period. The rainfall caused flooding and mudslides, resulting in about $34 million in damage (1970 USD); 186 homes were destroyed, and 700 people were left homeless. The flooding killed up to 50 people on the island. Elsewhere in the Lesser Antilles, the storm killed one person on Dominica from heavy rainfall, and in Guadeloupe heavy damage to the banana crop was reported.

The origins of Tropical Storm Dorothy were from a tropical wave that moved off the coast of Africa on August 13. It tracked generally westward, developing into a tropical depression on August 17 about 1375 mi (2210 km) east of Tobago in the Lesser Antilles. Two days later, it strengthened into Tropical Storm Dorothy, while located about 500 mi (800 km) east of the Lesser Antilles, with its intensity confirmed by the Hurricane Hunters.

With light vertical wind shear and warm water temperatures, the National Hurricane Center (NHC) remarked on August 19 that "hurricane status would probably be attained this afternoon or tonight." Its track was expected to continue generally west-northwestward, influenced by a ridge near the Bahamas, and within 60 hours Dorothy was forecast to be north or over Puerto Rico. However, a subsequent Hurricane Hunters flight reported a more westerly motion, which would bring its track through the central Lesser Antilles. Tropical Storm Dorothy gradually intensified, reaching peak winds of 70 mph (110 km/h) on August 20 just east-northeast of Barbados. Hurricane Hunters confirmed the intensity, though the flight also reported a weakness of low-level inflow. Despite maintaining winds of just below hurricane-force, there was no evidence of an eyewall on radars as the storm approached the Lesser Antilles. Late on August 20, the storm moved across Martinique into the Caribbean Sea, during which its low-level circulation became disorganized.