Long-term Trends In Hurricanes


Although there is a rise in the number of storms and cyclones in the Atlantic, there are no global trends in hurricanes to follow. Generally speaking, the annual number of tropical cyclones across the globe remains at about 87 ± 10. The lack of consistent historical data in some basins makes it difficult for the climatologists to analyze the activity trends in hurricanes.


But there are evidences to prove that the intensity and power of hurricanes is increasing. Records of hurricane activity worldwide illustrate an increase of both the wind speed and the duration of hurricanes. The energy released by the average hurricane seems to have increased by around 70% in the past 30 years. Atlantic storms and hurricanes are becoming more damaging financially. Since 1990, US has witnessed five of the ten most expensive storms in its history, with damages surpassing billions of dollars.

Moving on with the subject of long term Hurricanes trends, it is often seen that because of the risk of hurricanes, many coastal regions are thinly populated between major ports. Most often, the most brutal portions of hurricanes hitting the coast may have gone unmeasured in some instances. Before the age of hurricane reconnaissance aircraft and satellite meteorology, the number of intense hurricanes in the official records was limited.

Recent records reveal that activity trends in hurricanes show a clear increase in their number and strength.


The number and strength of Atlantic cyclones may experience a 50–70 year cycle, observing the long term trends in hurricanes. This is known as the Atlantic Multidecadal Oscillation. Following the hurricanes trends and activity back to the early 18th century,

there were five periods  which had an average of 3–5 major hurricanes per year and lasting 40–60 years. Then there were six other periods averaging 1.5–2.5 major hurricanes per year and which lasted 10–20 years. A decadal oscillation relating to solar irradiance was accountable to enhance or weaken the number of major hurricanes by 1–2 per year.


Studying the recent activity trends in hurricanes, few above-normal hurricane seasons have occurred during 1970–94. Destructive hurricanes have occurred frequently from 1926–60. During the seasons of 1900–25, the tropical hurricanes were less frequent however many powerful storms formed during 1870–99. 19 tropical storms were formed

during the 1887 season, of 11 strengthened into hurricanes.


Before the age of satellite in 1960, tropical storms or hurricanes went unobserved. Proxy records based on paleotempestological research have reflected major activity trends in hurricanes along the Gulf of Mexico coast. Few major hurricanes have hit the Gulf coast during 3000–1400 BC. But their landfall probabilities have increased by 3–5 times and this variability has been credited to long-term shifts in the position of the Azores High. It may also be associated to changes in the force of the North Atlantic Oscillation.


After going through the above info on long term trends in hurricanes would surely have widened tour perspectives on hurricanes.