Snow Hurricane of 1804

1804 Snow hurricane

Category 2 hurricane (SSHWS/NWS)
Map of Massachusetts at the time of the 1804 snow hurricane
Formed	4 October 1804
Dissipated	11 October 1804
(Extratropical after 10 October)
Highest winds	1-minute sustained: 110 mph (175 km/h)
Lowest pressure	977 mbar (hPa); 28.85 inHg
Fatalities	16 direct
Damage	$100,000 (1804 USD)
Areas affected	Caribbean Sea, South Carolina, Virginia, Mid-Atlantic States, New England, and southeastern Canada
Part of the 1804 Atlantic hurricane season

The 1804 Snow hurricane (also known as the Storm of October 1804) was the first tropical cyclone in recorded history known to produce snowfall, with Hurricane Ginny in 1963 and Hurricane Sandy in 2012 being the next such systems to do so. An unusual late-season storm in 1804, it yielded vast amounts of snow, rain, and powerful winds across the northeastern United States. Prior to its approach towards the East Coast of the United States, it passed through the Caribbean Sea on 4 October, and later emerged near Georgetown, South Carolina. By early on 9 October, a trough near the Virginia Capes turned the disturbance toward New England. Soon thereafter, the hurricane's abundant moisture clashed with an influx of cold Canadian air, leading to the deepening of the resulting pressure gradient and provoking inland intensification. While situated over Massachusetts, it attained its peak intensity of 110 mph (175 km/h), undergoing an extratropical transition. Even as it drifted towards the Canadian maritimes, consequently gradually weakening, precipitation persisted for another two days before the snowstorm finally subsided on 11 October.

Due to its unusual nature, both heavy snowfall and strong winds caused a swath of devastation stretching from the Mid-Atlantic states to northern New England. In the Middle-Atlantic region, moderate damage occurred at sea but little was noted inland. In New England, strong gusts inflicted significant damage to numerous churches. Widespread residential damage, in contrast, was mostly negligible and had no lasting consequences. Thousands of trees were knocked over, obstructing roads and fiscally damaging the timber industry throughout the region. Cold temperatures, wet snow, and high winds downed numerous branches in fruit orchards, froze potato crops, flattened dozens of barns, and killed over a hundred cattle. In general, the agriculture, shipping, timber, and livestock trades suffered most acutely following the passage of the snow hurricane, while structural damage was widespread but generally inconsequential.