In recent days, the formation of a cyclone in the Bay of Bengal has already been announced. Today, the system has now shown clear structures for the first time and reached storm strength – criteria required to name a tropical storm. The storm has been christened Mocha and will move northward in the coming days, reaching the coast of Myanmar and Bangladesh by the turn of the week.
The disaster takes its course...
It has been looming over the past few days, now the disaster is imminent. Cyclone Mocha (pronounced as Mocha) is heading towards the border region of Bangladesh and Myanmar in these hours and will hit land during Sunday. The storm system is both impressive and frightening. The image below shows a well-developed eye of what is now considered a Category 5 (out of 5) tropical storm.
Fig. 1: Infrared image of Mocha, low temperatures show a high cloud top; Source: CIMSS
Currently, Mocha is exhibiting wind speeds of 240 km/h, with 1-minute gust peaks even reaching nearly 300 km/h. It is expected to maintain this intensity for the next several hours before weakening somewhat ahead of landfall due to high wind shear and interaction with land surfaces. The eye is expected to make landfall near Sittwe on Sunday afternoon/evening (early Sunday afternoon in Switzerland). Currently, a third or fourth category tropical storm is expected at the time of landfall – near the coast, meaning maximum winds of over 200 km/h. In addition to devastating damage from the winds, there are other dangers. On the one hand, an extreme storm surge with heights of several meters and heavy rainfall with locally several hundred liters of rain per square meter must be expected. This is a particularly fatal combination because the coastal area is relatively flat, densely populated and in a river delta with marshes. In addition, landslides are imminent in the relatively nearby hills. Even though evacuations are currently in full swing, it will unfortunately not be possible to bring everyone to safety. Great suffering with many deaths must be feared.
Fig. 2: This is how the wind field might look just before shore leave; Source: Tropical Tidbits
A sad look into the history books
Since 1970, three different cyclones have claimed more than 100,000 lives in this region. The most globally deadly cyclone struck the Ganges delta farther west on Nov. 12, 1970, causing an extreme storm surge that claimed between 300,000 and 500,000 lives. The 1991 Bangladesh cyclone is also among the world's deadliest tropical storms, killing 140,000 people. Fifteen years ago, Cyclone Nargis – hit land a little further south in Myanmar compared to Mocha –, destroying thousands of homes and killing around 100,000 people.
The list of those storms shows the great vulnerability of this region – and this time will probably not be much different...
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