1993 North American storm complex
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| Storm type: | Cyclonic blizzard, Nor'easter | |
| Formed: | March 11, 1993 | |
| Dissipated: | March 15, 1993 | |
| Maximum amount1: |
50+ inches (130+ cm) | |
| Lowest pressure: |
960 mbar (hPa) | |
| Damages: | $6-10 billion (2005 USD) [citation needed] | |
| Fatalities: | 300 total | |
| Areas affected: | Most of eastern and southern North America | |
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1Maximum snowfall or ice accretion |
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The 1993 North American storm complex, also known as the ’93 Superstorm, the (Great) Blizzard of 1993, or the Storm of the Century, was a large cyclonic storm that occurred on March 12–March 15, 1993, on the East Coast of North America. It is unique both because of its intensity as well as its massive size and wide-reaching effect. At its height the storm stretched from Canada to Central America, but its main impact was on the Eastern United States and Cuba. Areas as far south as Atlanta, Georgia received 5 to 50 inches (13 to 130 cm) of snow, accompanied by hurricane-force wind gusts and record low barometric pressures. Farther south from Florida down to Cuba, hurricane-force winds produced extreme storm surges in the Gulf of Mexico, which along with scattered tornadoes killed dozens of people.
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[edit] Formation
Weather forecasters saw well in advance that the storm would be extremely powerful, citing a confluence of factors said to occur about once in 500 years. A "disorganized area of low pressure" that formed in the Gulf of Mexico (which, being warm by March, is a frequent source of spring snowstorms) joined an arctic high pressure system in the Midwestern Great Plains, brought into the mid-latitudes by an unusually steep southward jet stream. These factors combined to produce unusually cold temperatures across the eastern half of the United States.
[edit] The storm
This storm complex was massive, affecting over 27 U.S. states and much of eastern Canada. Bringing cold air along with heavy precipitation and hurricane force winds, it caused a blizzard over much of the area it affected. The storm brought snow as far south as northern Florida, thundersnow from Texas to Pennsylvania, and whiteout conditions. Some affected areas saw more than 3.5 feet (1.0 m) of snow, and snowdrifts were as high as 35 feet (10.0 m). Central and Southern Florida saw no snow, but tornados and derechos, resultant from the storm, occurred there and in Cuba. Responsible for 300 deaths and the loss of electric power to over 10 million, it is purported to have been directly experienced by over 130 million people in the United States, about half the country's population at that time. Every airport from Halifax, Nova Scotia to Atlanta, Georgia was closed for some time because of the storm. The volume of the storm's total snowfall was later computed to be 12.91 mi³ (53.96 km³), an amount which would weigh (depending on the variable density of snow) between 5.4 and 27 billion tonnes.
Temperatures accompanying the storm were unseasonably cold for early spring: average daily maximum temperatures, in mid-March, are around 46°F (8°C) in Boston, 51°F (11°C) in Philadelphia, Pennsylvania, and 65°F (18°C) in Atlanta. During the 1993 storm, these places were all near or below freezing, and parts of New England saw daily maximum temperatures as low as 14°F (-10°C). Record low temperatures for March were recorded in much of the Southern U.S.
Barometric pressures recorded during the storm were also unusually low: readings of 28.35 inHg (960 mb or hPa) were observed in New England. Usually, such low readings are observed only in hurricanes (generally of Category 2 or 3 intensity on the Saffir-Simpson hurricane scale), which peak at almost the exact opposite time of year, or in other cyclonic storms far out to sea. It also pushed a storm surge ashore on the Florida panhandle, drowning a few people taken by surprise at the storm's ferocity. (This incident is featured occasionally on reruns of Storm Stories.)
As one of the most powerful storms in recent history, the storm has been described as the "Storm of the Century" by many of the areas affected. The last blizzard to have such an effect on the Southeast was the Great Blizzard of 1899.
[edit] Impact
In the South, where public works facilities (in most areas) generally have no reason to be prepared for snow removal, the storm is vividly remembered because it resulted in a complete shutdown of that region for three days. Cities that usually receive little snowfall, such as Chattanooga, Tennessee, received anywhere from 2 to 4 feet of snow. The psychological impact in the Southern states, where average high temperatures in March tend to run into the 60s Fahrenheit (the upper teens Celsius), was magnified by the fact that it struck a week before spring. A NASCAR event at Atlanta Motor Speedway had to be postponed a week due to the storm; Birmingham recorded a record low of 2 degrees fahrenheit during the storm.
The weight of record snows collapsed many factory roofs in the South, and snowdrifts on the leeward sides of buildings caused a few decks with substandard anchors to fall from homes. Though the storm was forecast to strike the snow-prone Appalachian Mountains, hundreds of people were nonetheless rescued from the Appalachians, many caught completely off-guard on the Appalachian Trail, or visiting cabins and lodges in remote locales. The heaviest snow recorded was at Newfound Gap, where U.S. 441 crosses the Tennessee and North Carolina border, with five ft (1.5 m), plus drifts; snowfall totals of between 2 and 3 feet were widespread across northwestern North Carolina. Boone, North Carolina - in a high-elevation area accustomed to heavy snowfalls was nonetheless caught off guard by 24 hours of below zero temperatures along with storm winds, which (according to NCDC storm summaries) gusted as high as 110 miles per hour. Electricity was not restored to many isolated rural areas for a week or more.
Farther to the South, numerous supercells developed over the state of Florida, spawning eleven tornadoes and killing seven people. Nearly 60,000 lightning strikes were recorded as the storm swept over the country, for a total of seventy-two hours.
Overall, the Blizzard of 1993 caused a total of $6.6 billion of damage, making it the fourth costliest storm in US history.
Across the Northeastern states, the storm put down an average of 15 inches (40 cm) of snow, which, though most certainly heavy, is not legendary by most local standards, but still somewhat unusual for mid-March, especially for the southernmost parts of the region such as the Baltimore-Washington area. New England residents tend to point to the Blizzard of 1978 as their "storm of the century," due largely to its unrelenting snowfall, which managed to incapacitate the weather-hardened region, while Mid-Atlantic residents tend to point to the Blizzard of 1996 for similar reasons. Based on widespread effects, barometric pressures, wind speeds and satellite images, however, there is little doubt that the storm of 1993 was the more remarkable.
[edit] Subtropical derecho
In addition to the blizzard, a serial derecho occurred in the U.S. state of Florida extending to Cuba on March 12 and 13, 1993. Straight-line winds gusted above 100 mph/85 kts (160 km/h) at many locations in Florida as the squall line moved through.
Besides producing record low barometric pressure, and one of the nation's biggest snowstorms, the low produced a potent squall line ahead of its cold front. The squall line produced a serial derecho as it moved into Florida and Cuba around midnight on March 13. It finally moved out of Cuba just before sunrise. There was widespread and significant damage in Cuba, with damages estimated as intense as F2 [1]. A substantial storm surge was also generated.
The supercells in the derecho produced ten tornadoes in the United States. One tornado killed three people when it struck a home which later collapsed, pinning the occupants under a fallen wall.
In Cuba wind gusts reached 100 mph (160 km/h) in the Havana area. A survey conducted by a research team from the Institute of Meteorology of Cuba suggests that the maximum winds could have been as high as 130 mph (210 km/h). It is the most damaging squall line ever recorded in Cuba.
The derecho killed seven in Florida and injured 79. The event resulted in 10 deaths in Cuba and caused US$1 billion in damage in Cuba alone.
