Thursday, February 18, 2010

Notable Hurricanes: Longevity; Part 3

This is the conclusion of a three part post. For the first part see here. For the second part see here.

#3 Hurricane Inga (1969) September 20-October 15 24.75 days (from formation to final extratropical transition)

The depression that became Inga formed on September 20 from a tropical wave that moved off of Africa a few days before. The system quickly became a tropical storm, but then was a depression again until the 28th. Upon turning northward, Inga became a hurricane and made a very tight loop southeast of Bermuda, before making a bigger loop and becoming a major hurricane, reaching its peak intensity of 115 mph winds and a pressure of 964 millibars. Still moving slowly, Inga started to weaken halfway through its loop and dissipated on October 15. Although Inga was very long lived, it didn't affect land and no damage resulted. Inga had an ACE of 31.64.

Track of Inga.

#2 Hurricane Ginger (1971) September 5-October 3 27.25 days (from formation to final extratropical transition)

Hurricane Ginger originated from a very large trough of low pressure spanning from the Gulf of Mexico, into the Bahamas, and through parts of the Caribbean. A total of four tropical cyclones, one depression, one tropical storm, and two hurricanes, could be traced back to this low-pressure area. The second of these to form from the trough was Ginger. The tropical depression that became Ginger was recognized as such on September 5, and drifted for much of the next four days. Heading southeast, and then northeast, the depression became Tropical Storm Ginger on September 10. Ginger started to accelerate east-north-east, and rapidly gained intensity before becoming a hurricane. On September 14, now a Category 2 hurricane, Ginger reached its peak intensity of 105 mph winds and a minimum sea level pressure of 959 millibars. Then, a strong high pressure system to the northeast of Ginger slowed its movement, turned it around, and weakened it to a Category 1 hurricane. It stalled for a few days, making a very tight loop on the 19th and 20th of September, before adopting a sluggish, but steady, westward movement. On September 23, Ginger passed its closest to Bermuda. Ginger stalled again a day later and drifted from the 24th to the 29th. During this time, Project Stormfury tried to weaken the storm on September 26 and September 28. Project Stormfury is a program that attempted to dissipate the clouds associated with tropical cyclones by "seeding" them, or dropping chemicals into the eyewall to weaken it. Ginger was the last hurricane to be used for this experiment due to lack of financial support and the fact that it simply didn't seem to work. The idea is sound in theory, but execution isn't feasible for two reasons. Firstly, it costs too much to carry a significant amount of chemicals to high altitudes, and second that the hurricanes quickly redevelop due to the abundance of moisture in ocean air. Soon after Ginger turned to the northwest, and became a Category 2 hurricane again, before weakening to a Category 1. On September 30, Ginger struck North Carolina, still a hurricane, but barely. It weakened inland and was nearly stationary for the first few days of October before becoming extratropical and moving off the coast the east on October 3, joining the Atlantic Ocean once more. Ginger caused some damage, $53 million adjusted for inflation ($10 million at the time), but no deaths resulted. Most of the damage came from the central coast of North Carolina, where a wide area had received over ten inches of rain from Ginger. Ginger had an ACE of 44.19.

Track of Hurricane Ginger, spanning nearly a month.

#1 Hurricane Three (1899) August 3-September 4 28 days (from formation to final extratropical transition)

The tropical storm destined to be named Hurricane San Ciriaco for the place it damaged formed on August 3, 1899. It quickly intensified in the favorable region and was a hurricane by August 5 and a major hurricane soon afterward. It brushed the easternmost islands of the Caribbean shortly before striking Puerto Rico, and its namesake, San Ciriaco, at its peak intensity as a Category 4 of 150 mph winds and an approximate pressure of 930 millibars. After devastating Puerto Rico, the system moved onward to the Dominican Republic, passing north of the island. Over the next four days or so, the hurricane passed through the Bahamas, still a Category 3, before striking North Carolina on August 17. It emerged off of North Carolina as a minimal Category 1 hurricane, and sped off eastward into open waters becoming extratropical on August 22. However, the system was pushed south for a time, and regained enough tropical characteristics to be a tropical storm again on August 26. The tropical storm slowly moved north, and then slowly east. The storm intensified and accelerated east, briefly becoming a Category 1 hurricane on October 3rd before losing its tropical features and becoming extratropical for the last time the next day. Although the damage caused by this storm cannot be calculated in dollars, it can be measured as one of the deadliest tropical cyclones in history, causing 3,433 fatalities, most of them (about 3,200 of them) occurring in Puerto Rico. Hurricane San Ciriaco also had the highest ACE of any Atlantic hurricane, at 73.57.

Track of Hurricane San Ciriaco, a long-lived and deadly hurricane.

Through this and two other posts, the top ten Atlantic hurricanes it terms of longevity have been listed. However, one record remains, the longest lived tropical cyclone in the world. Hurricane San Ciriaco is still second in the world, behind only a remarkable cyclone that was both a hurricane and a typhoon in the Pacific Ocean, due to the fact that it crossed the International Date Line. A summary of the cyclone is shown below.

#1 (world) Hurricane/Typhoon John (1994) August 11-September 10 31 days (from formation to final extratropical transition)

Due to the advanced reanalysis that occurs for all tropical cyclones after (sometimes years after) they form, this particularly powerful hurricane that formed in the Pacific, can have its wave origins trace back to the Atlantic. On July 25, 1994, a tropical wave moved off Africa, and moved westward into unfavorable conditions for development. Therefore, the wave didn't become a low pressure system until it entered the East Pacific Ocean through Central America and became a tropical depression on August 11. It quickly became a tropical storm, but wind sheer was ripping at the system, and Tropical Storm John couldn't strengthen until August 19, when John had nearly passed out of the reach of the sheering system. Upon entering this favorable zone, John became a hurricane, and soon, a major hurricane. On August 20, John passed out of the East Pacific, into the Central Pacific. Unlike the Atlantic, whose boundaries are easily measured by land and the equator, the Pacific is split into three separate basins, the East, the Central, and the West. The East Pacific goes from the west coast of Mexico and the U.S. out to a line. In this area there is an alphabetic name list, similar to the Atlantic. A cyclone that passes from the East to the Central Pacific is still called a hurricane, and retains the same name. However, cyclones that form in this basin follow a different name list that does not go in any alphabetical order, because of the relative lack of cyclones in the region. Therefore, when Hurricane John entered the Central Pacific and switched basins, it was still was Hurricane John, and was still gaining intensity. By the time John was at its closest approach to the Hawaiian Islands it was a Category 5 hurricane, but, fortunately for the islands, John was 345 miles away. Despite this, John's outer rain bands caused a significant amount of damage. However, the system couldn't turn towards Hawaii because the usual high pressure system over the islands was blocking all cyclones from turning north. Later that same day of its closest approach, on August 22, John reached its peak intensity of 175 mph winds and a pressure of 929 millibars. However, the pressure was probably much lower than this, because the pressure had last been taken when John was not at its peak intensity. Now, John took a northwest turn, and steadily weakened to Category 1 hurricane strength. Over the next days, however, John regained some of its intensity and reached Category 4 status. It was at a secondary peak with 135 mph winds when it crossed the International Date Line and entered the West Pacific. The West Pacific had another name list still, with another major difference. The scale of intensity was also different. Instead of going tropical depression, tropical storm, hurricane, it went tropical depression, tropical storm, typhoon, super typhoon. Therefore, when John crossed the date line on August 27, it was still John, but a typhoon, not a hurricane. However, upon crossing the date line, John had nearly stopped moving and by September 1, John was a stationary tropical storm. John went through a slow loop, first east, and then back west, still a tropical storm. By the time this loop ended, a trough was moving in, forcing John quickly to the northeast. On September 8, John had crossed back into the Central Pacific and was still a tropical storm. John attained hurricane strength again and reached 90 mph winds before finally becoming extratropical on September 10. John hadn't caused much damage and the only damage was to Hawaii and to Johnston Atoll in the north-central Pacific. John's ACE was not accurate because it had crossed three basins, but it is estimated to be in the 50's.

Hurricane John at primary peak intensity as a strong Category 5 hurricane.

Track of John.

Some of the above cyclones are the most notable in the world, and many have some of the most erratic tracks of any cyclones ever.

The information on this post can be credited mostly to wikipedia, which, in turn, got its information from the National Hurricane Center that keeps records of Atlantic tropical cyclones dating back to 1850. Any cyclones before that time cannot be on the above list, due to lack of information.