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The 1846 San Francisco de Borja hurricane (also known as the Great Havana hurricane of 1846) was the most intense tropical cyclone in recorded history for 78 years and the first known Category 5-strength hurricane to strike Cuba. The first indications of the formation of a disturbance were first noted on 5 October in the Caribbean Sea, but little else was known until the storm approached Cuba on 10 October. There, it brought extreme winds and the lowest known atmospheric pressure of the time – 938 mbar (27.70 inHg) – a record which remained unbroken until the development of a later cyclone in 1924. It soon curved toward Florida, where it maintained its intensity, continuing to rapidly hasten northward along the East Coast of the United States to New England. It entered an extratropical transition while situated over New York on 13 October, producing intense Category 2-force winds and unusually little precipitation. Eventually, the gale dissipated over the Canadian Maritimes the following day as a markedly weaker storm. In Cuba, the storm caused hundreds of deaths, capsized dozens of ships, obliterated buildings, uprooted trees, and ruined crops. Many towns were wholly destroyed or flattened and never recovered, while others disappeared entirely. Damage in the United States was considerably better-chronicled despite being less severe. In Key West, widespread destruction was noted, with 40 deaths, many vessels rendered unfit, and widespread structural damage, with several buildings swept off of their foundations and hundreds of others flattened. Few supplies arrived in the following days and relief efforts were gradual, with few resources within the town's vicinity. Along other sections of the southeastern coast, copious rainfall and moderate winds impacted agriculture, shipping, and residences. As it tracked along the Middle-Atlantic coast, similar effects were reported: there, the gale inundated many areas, impeded communications, destroyed railroads and canals, and flattened structures. Despite extensive damage, only two deaths were recorded outside Cuba and Florida. Along its entire track, the hurricane caused $338,000 in losses and at least 164 deaths. Unusual in many aspects, the 1846 Havana hurricane was the most intense of its time. Though atmospheric pressure readings in Cuba reached as low as 916 mbar (27.06 inHg), the meteorological historian Jose Fernandez-Partagás re-evaluated several possible pressure records, concluding that the cyclone's minimum pressure was likely closer to 938 mbar (27.70 inHg); even so, it maintained the title of having the lowest recorded pressure measurement until 1924, 78 years later. Although no reliable wind measurements were available at the time, a separate study also estimated that it produced Category 5-strength winds, making it the first known storm to strike Cuba at such an intensity. As a result of the tropical cyclone's extreme intensity, ecological and geographical features were permanently altered in many areas. Sand Key, which completely submerged during the course of the hurricane, wholly re-emerged by December of that year, albeit not in its original position; meanwhile, ecological damage remained evident for decades in Key West. == Meteorological history == The hurricane's origins can be traced to the central Caribbean Sea on 5 October.〔Chenoweth 2006, p. 234〕 The following day, its passage south of Jamaica was observed,〔Tannehill 1938, p. 156〕 and soon later, the hurricane transited across the Cayman Islands, producing relatively high winds.〔 During the late evening of 10 October, winds began to increase on the island of Cuba, culminating the following morning; while the strongest winds were originally in the storm's northeastern sector, they were later noted in its northwest. Its eye presumably passed slightly east of Havana while maintaining an atmospheric pressure of 916 mbar (27.06 inHg).〔Ludlum 1963, p. 151〕 This was accompanied by Category 5-force winds on the modern-day Saffir–Simpson hurricane wind scale,〔Landsea et al. 2012, p. 883〕 defined as 1-minute maximum sustained winds of at least 157 mph (252 km/h). Despite the reading, a 1993 analysis by weather historian Jose Fernandez-Partagás calculated a corrected sea-level pressure at 938 mbar (27.70 inHg); even so, the value maintained the hurricane as the most intense in recorded history.〔Partagás 1993, p. 1〕 It arrived at Key West the morning of 11 October, soon after its departure from Cuba, with undiminished intensity.〔 The storm gradually meandered toward Tampa Bay, and eventually arrived on that afternoon of 11 October, its effects persisting through the following morning.〔Ludlum 1963, p. 152〕 Winds, which initially swept northeasterly at force 4 during the early evening, recurved toward the southeast and peaked at force 8 the following morning. Weather historian David Ludlum tracked the hurricane's path past Cedar Key, noting the disturbance's northeastward curve as it neared Jacksonville.〔Ludlum 1963, p. 153〕 Advancing northward, the once-powerful hurricane weakened, with somewhat higher atmospheric pressures and winds of less severity reported at Charleston, South Carolina. Paralleling the coast while situated inland, it hastened quickly toward the north, swiftly passing through North Carolina and arriving in the Chesapeake Bay region by 13 October.〔 Southeasterly gusts persisted as the storm continued its northerly progression inland along the course of the East Coast of the United States. After reaching Washington, D.C. in the early morning, it arrived near New York City by sunrise, and transited across Boston during the afternoon of 13 October. The storm likely underwent an extratropical transition by the time it arrived in New York state, elongating linearly east-to-west.〔Ludlum 1963, p. 94〕 The gale's winds swept toward the southeast with a brief hiatus in the early evening. As it neared New England, it produced little precipitation yet incited intense gusts, peaking at force 9-strength in the vicinity of New Bedford, Massachusetts.〔Ludlum 1963, p. 95〕 The cyclone's diameter over New England, at its largest point, reached , accompanied Category 2-force winds.〔Boose et al. 2001, p. 40〕 The system was last sighted on the morning of 14 October, rapidly weakening as it meandered into the Canadian Maritimes. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「1846 San Francisco de Borja hurricane」の詳細全文を読む スポンサード リンク
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