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Five Most Extreme Hydrologic Events that changed the World

Typhoon Tip, Philipines(Collected from : CSMonitor)


Devastating storms, severe flood, acute famine conditions, etc. hydrological events of extreme nature has changed human history. Any event which is not normal is known as an abnormal event. In the case of hydrology, an event that has a return period of more than 100 years is considered Extreme.

According to Herring(2020) of Climate.gov, "An extreme event is a time and place in which weather, climate, or environmental conditions—such as temperature, precipitation, drought, or flooding—rank above a threshold value near the upper or lower ends of the range of historical measurements."

Though the threshold is not objective, few researchers have defined "extreme events as those that occur in the highest or lowest 5% or 10% of historical measurements". Some have described events by their deviation from the mean, or by their occurrence interval.  

Here the most severe five extreme hydrologic events were discussed which has changed the pathway of human history after the occurrence of these events. The impact of such events was experienced many decades after the event has occurred.

How have I  selected the events?

At the time of selection, we have considered the death toll due to the event, return period, and impact on the future generation as the criteria. The decision-making tool "ODM" was used to find and sort the events as per their severity and placed them below:

1) Typhoon Tip, Philippines

 The strongest tropical cyclone recorded worldwide, as measured by minimum central pressure, was Typhoon Tip, which reached a pressure of 870 hPa (25.69 inHg) on October 12, 1979.

 2) 1999 Odisha cyclone. India

The 1999 Odisha cyclone (IMD designation BOB 06,[1] JTWC designation 05B[3]) was the most intense recorded tropical cyclone in the North Indian Ocean and among the most destructive in the region which occurred on 29th October 1999 when the winds of 260 km/h (160 mph) and a record-low pressure of 912 mbar (hPa; 26.93 inHg) was observed in the Bhubaneswar and various places in Odissa. The storms dissipated on 4 November over the Bay of Bengal. Not only Bhubaneswar, but a complete breakdown of essential services was also observed in Balasore, Bhadrak, Cuttack, Dhenkanal, Jagatsinghpur, Jajpur, Keonjhar, Kendrapara, Khurda, Puri, Mayurbhanj, and Nayagarh. The entire green cover of the Bhubaneswar city was destroyed in one night. In total, 12.9 million people were affected by the storm; and around 9,887(approx) were killed

3) 1931 China floods

The 1931 China floods, or the 1931 Yangtze–Huai River floods, were a series of floods that occurred from June to August 1931 in China, hitting major cities such as Wuhan, Nanjing, and beyond, which eventually culminated into a dike breach along Lake Gaoyou on 25 August 1931.

4) 1987, the Bihar Flood, India

In 1987, the Bihar state of India witnessed one of its worst floods till then. The flood occurred due to the overflow of the Koshi river; which claimed the lives of 1,399 humans, 302 animals and public property worth INR ₹68 billion (US$900 million). After this flood Koshi changed his flow path.

5) Drought in China and India 1876-79

The most severe drought was in northern China in 1876-79, when between 9 and 13 million people are estimated to have died after the rains failed for three consecutive years. At around the same time (1876-78), approximately 5 million Indians died when the monsoon failed in successive years.


Signing off
Mrinmoy


Founding and Honorary Editor HydroData 
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