Hurricane Greta (1956)
Encyclopedia
Hurricane Greta was the largest Atlantic hurricane ever recorded, with tropical storm-force winds spanning an area 1,200 miles (1,930 km) wide. Originating from a tropical depression near Jamaica
on October 30, the system initially featured non-tropical characteristics as it tracked northward. By November 2, the system began producing gale-force winds around the low pressure area; however, winds near the center of circulation were calm. By November 3, the system intensified into a tropical storm and was named Greta. Quickly strengthening, Greta attained hurricane-intensity on November 4 and by the following morning, the hurricane had rapidly intensified
into a Category 4 storm with winds peaking at 140 mph (220 km/h). Shortly after, Greta began to weaken as it tracked over cooler waters. The storm eventually became extratropical
on November 7 over the central Atlantic. Although Greta did not directly impact land as a tropical storm or hurricane, it generated large swells that impacted numerous areas. One person was killed in Puerto Rico and coastal damages from the waves amounted to roughly $3.6 million (1956 USD; $ USD).
near Jamaica
on October 30, 1956. A Navy reconnaissance plane recorded sustained winds of 35 mph (55 km/h) and found an area of low pressure
. Around this time, the system was classified as a tropical depression. Although a ship near the system discovered a cold-core circulation—a feature of non-tropical cyclones—it was classified as tropical. By October 31, the depression passed near the eastern edge of Haiti
and later crossed the eastern tip of Cuba
before entering the Atlantic Ocean. By the afternoon of November 1, the depression had moved through the central Bahamas and turned towards the northeast.
By this time, the central pressure of the depression had decreased to 998 mbar (hPa; 29.47 inHg) and gale-force winds were recorded over a large area but not near the center. The system was compared to that of a Kona low, a large-scale subtropical cyclone that forms near Hawaii
. Early on November 2, the depression turned northwest in response to an area of high pressure
over the central Atlantic. Later that day, the first scientific mission into a hurricane with two planes took place when two research aircraft flew into Greta. During the day, an Air Force B-50 aircraft and NHRP B-47 high altitude jet flew into the storm. The storm executed a counter-clockwise loop, ending on November 3, during which time numerous reconnaissance missions were flown into the system. On November 3, the depression was upgraded to Tropical Storm Greta as the circulation featured tropical characteristics. By this time, the storm had also begun a southeastward track.
Continuing to intensify, Greta attained hurricane status on November 4 and later that day it attained Category 2 status on the modern day Saffir–Simpson Hurricane Scale. After reaching this intensity, the hurricane turned northeastward and accelerated. Rapid intensification
took place shortly after, fueled by favorable mid-latitude conditions. On November 5, Greta attained Category 4 status, with winds peaking at 140 mph (220 km/h), making it the strongest storm of the 1956 season. A reconnaissance mission around this time recorded a minimum pressure of 970 mbar (hPa; 28.64 inHg).
Around the time of peak intensity, Greta was an extraordinarily large hurricane, with the gale-diameter of the storm extending roughly 1,200 mi (1,930 km), making the hurricane the largest ever recorded in the Atlantic basin. After attaining its peak intensity, the storm began to move over cooler waters, resulting in the circulation becoming elongated. Early on November 6, Greta weakened to a Category 3 hurricane and continued accelerating to the east-northeast. Several hours later, the system weakened to a Category 1 hurricane and by November 7, Greta transitioned into an extratropical cyclone
over the central Atlantic.
alone, coastal structures sustained roughly $1.2 million (1956 USD; $9.6 million 2009 USD) in damages. In Puerto Rico
, waves up to 20 ft (6.1 m) caused significant damage and resulted in the death of one person after he did not evacuate his home. Swells up to 25 ft (7.6 m) were recorded in the Virgin Islands
. In Guadeloupe
, 80% of the port installations were destroyed by rough seas. In all, damages from Greta amounted to roughly $3.6 million (1956 USD; $ USD).
Jamaica
Jamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...
on October 30, the system initially featured non-tropical characteristics as it tracked northward. By November 2, the system began producing gale-force winds around the low pressure area; however, winds near the center of circulation were calm. By November 3, the system intensified into a tropical storm and was named Greta. Quickly strengthening, Greta attained hurricane-intensity on November 4 and by the following morning, the hurricane had rapidly intensified
Rapid deepening
Rapid deepening, also known as rapid intensification, is a meteorological condition that occurs when the minimum sea-level atmospheric pressure of a tropical cyclone decreases drastically in a short period of time. The National Weather Service describes rapid deepening as a decrease of...
into a Category 4 storm with winds peaking at 140 mph (220 km/h). Shortly after, Greta began to weaken as it tracked over cooler waters. The storm eventually became extratropical
Extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and...
on November 7 over the central Atlantic. Although Greta did not directly impact land as a tropical storm or hurricane, it generated large swells that impacted numerous areas. One person was killed in Puerto Rico and coastal damages from the waves amounted to roughly $3.6 million (1956 USD; $ USD).
Meteorological history
Hurricane Greta originated out of a tropical disturbance in the Intertropical Convergence ZoneIntertropical Convergence Zone
The Intertropical Convergence Zone , known by sailors as The Doldrums, is the area encircling the earth near the equator where winds originating in the northern and southern hemispheres come together....
near Jamaica
Jamaica
Jamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...
on October 30, 1956. A Navy reconnaissance plane recorded sustained winds of 35 mph (55 km/h) and found an area of low pressure
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
. Around this time, the system was classified as a tropical depression. Although a ship near the system discovered a cold-core circulation—a feature of non-tropical cyclones—it was classified as tropical. By October 31, the depression passed near the eastern edge of Haiti
Haiti
Haiti , officially the Republic of Haiti , is a Caribbean country. It occupies the western, smaller portion of the island of Hispaniola, in the Greater Antillean archipelago, which it shares with the Dominican Republic. Ayiti was the indigenous Taíno or Amerindian name for the island...
and later crossed the eastern tip of Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
before entering the Atlantic Ocean. By the afternoon of November 1, the depression had moved through the central Bahamas and turned towards the northeast.
By this time, the central pressure of the depression had decreased to 998 mbar (hPa; 29.47 inHg) and gale-force winds were recorded over a large area but not near the center. The system was compared to that of a Kona low, a large-scale subtropical cyclone that forms near Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
. Early on November 2, the depression turned northwest in response to an area of high pressure
High pressure area
A high-pressure area is a region where the atmospheric pressure at the surface of the planet is greater than its surrounding environment. Winds within high-pressure areas flow outward due to the higher density air near their center and friction with land...
over the central Atlantic. Later that day, the first scientific mission into a hurricane with two planes took place when two research aircraft flew into Greta. During the day, an Air Force B-50 aircraft and NHRP B-47 high altitude jet flew into the storm. The storm executed a counter-clockwise loop, ending on November 3, during which time numerous reconnaissance missions were flown into the system. On November 3, the depression was upgraded to Tropical Storm Greta as the circulation featured tropical characteristics. By this time, the storm had also begun a southeastward track.
Continuing to intensify, Greta attained hurricane status on November 4 and later that day it attained Category 2 status on the modern day Saffir–Simpson Hurricane Scale. After reaching this intensity, the hurricane turned northeastward and accelerated. Rapid intensification
Rapid deepening
Rapid deepening, also known as rapid intensification, is a meteorological condition that occurs when the minimum sea-level atmospheric pressure of a tropical cyclone decreases drastically in a short period of time. The National Weather Service describes rapid deepening as a decrease of...
took place shortly after, fueled by favorable mid-latitude conditions. On November 5, Greta attained Category 4 status, with winds peaking at 140 mph (220 km/h), making it the strongest storm of the 1956 season. A reconnaissance mission around this time recorded a minimum pressure of 970 mbar (hPa; 28.64 inHg).
Around the time of peak intensity, Greta was an extraordinarily large hurricane, with the gale-diameter of the storm extending roughly 1,200 mi (1,930 km), making the hurricane the largest ever recorded in the Atlantic basin. After attaining its peak intensity, the storm began to move over cooler waters, resulting in the circulation becoming elongated. Early on November 6, Greta weakened to a Category 3 hurricane and continued accelerating to the east-northeast. Several hours later, the system weakened to a Category 1 hurricane and by November 7, Greta transitioned into an extratropical cyclone
Extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and...
over the central Atlantic.
Preparations and impact
Although Greta did not directly track over land as a tropical storm or hurricane, the size of the system contributed to large waves, exceeding 20 ft (6.1 m) in height over a large expanse of the Atlantic. Impacts from the storm were felt as far away as the eastern United States. The National Weather Bureau warned ships in the vicinity of the system to take precautions. St. Croix was nearly isolated and stressed into an emergency due to Greta after the storm's swells destroyed docks and prevented ships carrying food from reaching the island. Several light vessels were destroyed by Greta's gale-force winds and only schooners with little carrying capacity were able to make it to the island. Along the coast of Jacksonville, FloridaJacksonville, Florida
Jacksonville is the largest city in the U.S. state of Florida in terms of both population and land area, and the largest city by area in the contiguous United States. It is the county seat of Duval County, with which the city government consolidated in 1968...
alone, coastal structures sustained roughly $1.2 million (1956 USD; $9.6 million 2009 USD) in damages. In Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
, waves up to 20 ft (6.1 m) caused significant damage and resulted in the death of one person after he did not evacuate his home. Swells up to 25 ft (7.6 m) were recorded in the Virgin Islands
Virgin Islands
The Virgin Islands are the western island group of the Leeward Islands, which are the northern part of the Lesser Antilles, which form the border between the Caribbean Sea and the Atlantic Ocean...
. In Guadeloupe
Guadeloupe
Guadeloupe is an archipelago located in the Leeward Islands, in the Lesser Antilles, with a land area of 1,628 square kilometres and a population of 400,000. It is the first overseas region of France, consisting of a single overseas department. As with the other overseas departments, Guadeloupe...
, 80% of the port installations were destroyed by rough seas. In all, damages from Greta amounted to roughly $3.6 million (1956 USD; $ USD).