Hurricane Flora was an extremely deadly and devastating tropical cyclone that is among the deadliest Atlantic hurricanes in recorded history, with a death total of at least 7,193. The seventh tropical storm and sixth hurricane of the 1963 Atlantic hurricane season, Flora developed from a disturbance in the Intertropical Convergence Zone on September 26 while located southwest of the Cape Verde islands. After remaining a weak depression for several days, it rapidly organized on September 29 to attain tropical storm status. Flora continued to strengthen, reaching Category 3 hurricane status after moving through the Windward Islands and passing over Tobago, and it reached maximum sustained winds of in the Caribbean.
The storm struck southwestern Haiti near peak intensity, turned to the west, and drifted over Cuba for four days before turning to the northeast. Flora passed over the Bahamas and accelerated northeastward, becoming an extratropical cyclone on October 12. Due to its slow movement across Cuba, Flora is the wettest known tropical cyclone for Cuba, Haiti, and the Dominican Republic. The significant casualties caused by Flora were the most for a tropical cyclone in the Atlantic Basin since the 1900 Galveston Hurricane.<!-- defined by Template:Wettest tropical cyclones in Haiti -->
Meteorological history
The tropical wave that ultimately spawned Hurricane Flora moved off the coast of West Africa sometime late on September 23 or early September 24. The disturbance gradually became better organized as it moved west across the tropical Atlantic. Two disturbances comprising the complex were detected by the satellite, though it is unclear which particular disturbance became Flora. Weather observations were scant in the vicinity of Flora around the time it became a tropical depression, However, a KLM jet airliner en route to Paramaribo, Suriname, encountered disturbed weather east of the Lesser Antilles on September 28, prompting the Weather Bureau office in San Juan, Puerto Rico, to request special weather observations from ships in the area the next day and schedule an aerial reconnaissance mission into the storm for September 30.|alt=Grayscale radar image of the hurricane]]
Within the southeastern Caribbean Sea, Flora took a steady course towards Haiti's Tiburon Peninsula that curved progressively northwards with time. The hurricane's rate of intensification on October 1 had become more gradual, though the storm was continuing to strengthen. However, Flora began to strengthen quickly between October 2–3, with periodic aircraft reconnaissance missions finding increasing winds and deepening air pressures. with Flora's winds continuing to increase before reaching a peak of around 150 mph (240 km/h) by 18:00 UTC on October 4; this intensity is equivalent to a Category 4 hurricane on the modern Saffir–Simpson hurricane wind scale. Based on aircraft reconnaissance data, Flora had a minimum central air pressure of around 933 mbar (hPa; 27.55 inHg) and wind gusts of 180–200 mph (290–320 km/h) at the time of its peak strength.
thumb|left|[[Weather map#Constant pressure charts|Weather map on October 6 showing ridges west and east of Flora|alt=Contoured weather map]]
Changing atmospheric circulation patterns over the United States in early October 1963 were consequential in shaping Flora's trajectory leading up to and after the hurricane's landfalls on Haiti and Cuba. Although Flora's northward curve leading to its landfall on Haiti was spurred by the presence of a trough off the U.S. East Coast,