Why Cyclone Biparjoy Lasted For Nearly 10 Days Over Arabian Sea

Cyclone Biparjoy made landfall near Jakhau Port in Gujarat's Kutch district on Thursday evening after a 10-day journey across the Arabian Sea. Emergency teams were on standby for relief and rescue efforts, and about 100,000 people had been evacuated to safer locations in the state.

The storm had been moving slowly north in the Arabian Sea for eight days before it turned east on June 14.

The cyclone had maximum sustained winds of 125-140 kilometers per hour, however, it began to weaken several hours later, and by 2:30 am on Friday, its winds had decreased to 100 kilometres per hour with gusts up to 110 kilometres per hour.

But why did the very severe cyclonic storm spend such an unusually long time at sea?

Warm sea surface temperatures have helped Cyclone Biparjoy to last longer than any other cyclone in the Arabian Sea in recent history. As of June 15, the storm had already been sustained by the Arabian Sea for over nine days, and was on track to become the longest-lived cyclone in the basin, overtaking Cyclone Kyarr in 2019, which lasted nine days and 15 hours.

"The reason why Biparjoy has lasted so long is that it is feeding on warm waters in the Arabian Sea," said Raghu Murtugudde, visiting professor at IIT Bombay, as quoted by NASA. "Biparjoy is an example of how climate change-especially warming in the upper ocean-is contributing to cyclones moving slower and lasting longer."

Cyclone Biparjoy formed in the early morning hours of June 6. The sea surface temperatures in the Arabian Sea were unusually warm at the time, ranging from 31 to 32 degrees Celsius. This was 2 to 4 degrees Celsius above the average temperature for this time of year. Scientists believe that ocean temperatures must be above 27 degrees Celsius in order to sustain a tropical cyclone.

The unusually warm waters of the Arabian Sea supercharged Cyclone Biparjoy twice during its lifespan. The Joint Typhoon Warning Center (JTWC) reported that the storm's wind speed increased from 55 to 139 kilometers per hour (34 to 86 miles per hour) between June 6 and 7. Then, between June 9 and 10, Biparjoy intensified again, with wind speeds increasing from 120 to 196 kilometers per hour (75 to 122 miles per hour), making it a category 3 storm.

At least 22 people have been injured following Cyclone Biparjoy's landfall. Heavy rain accompanied by gusty winds brought down over 500 trees and electric poles, plunging around 940 villages in Gujarat into darkness. 

According to the IMD, heavy to extremely heavy rainfall is likely to continue in Saurashtra and Kutch until June 16.