May 12, 2023 - World

Tropical Cyclone Mocha poses grave threat to Bangladesh and Myanmar

Satellite image showing Tropical Cyclone Mocha spinning in the Bay of Bengal on May 12.

Satellite image showing Tropical Cyclone Mocha spinning in the Bay of Bengal on May 12. Image:

Powerful Tropical Cyclone Mocha is forecast to hit Myanmar on Sunday local time, while also affecting Bangladesh, as at least a Category 2 or 3 storm.

The big picture: The storm will strike one of the areas in the world that are most vulnerable to storm surge flooding, at a time when hundreds of thousands of Rohingya refugees are crowded into camps near Bangladesh's coast.

  • On Friday, Cyclone Mocha was continued to rapidly intensify overnight, with an eye becoming visible on satellite imagery, as the storm traversed warmer than usual ocean waters.
  • Continued rapid intensification is forecast, according to the Joint Typhoon Warning Center, and the storm could reach the intensity of a Category 4 hurricane before it nears the coast.
  • Slightly cooler ocean waters could weaken the storm slightly as it comes ashore, but it will already be accompanied by 50-foot waves and a storm surge that could reach 8 feet, per the World Meteorological Organization.

Zoom in: Most computer model projections, as well as forecasts from the JTWC in the U.S. and the Indian Meteorological Department, take the storm ashore between Cox's Bazar, Bangladesh, and near Sittwe, Myanmar.

Threat level: This region is extremely vulnerable to storm surge flooding, which is becoming even more of a threat with climate change-driven sea level rise.

  • Past cyclones in the Bay of Bengal have killed tens of thousands of people by flooding heavily populated, low-lying areas. However, Bangladesh has improved its storm early-warning programs in recent years.
  • With a repressive military government, Myanmar is more of a wild card in how prepared the country will be for such a powerful storm.
  • The governments of both countries have said that evacuations were being planned, per AP.

The storm is particularly concerning for the already dire humanitarian crises in both Bangladesh and Myanmar.

  • Cox’s Bazar is home to about 1 million Rohingya refugees, the WMO stated.
  • About 6 million people across Myanmar's coastal Rakhine state and the country's northwest are already in need of humanitarian assistance, according to the UN humanitarian agency.

Context: By increasing ocean temperatures at the surface and at deeper depths, as well as adding moisture to the atmosphere, human-caused climate change is making the rapid intensification of tropical cyclones like Cyclone Mocha more likely, studies have shown.

  • Climate change is also increasing the average rainfall amounts from landfalling tropical cyclones.
  • For example, a 2020 study published in the Proceedings of the National Academy of Sciences found that tropical cyclones are more likely to reach higher categories across much of the globe, including the Atlantic.

The bottom line: Cyclone Mocha could aggravate a preexisting humanitarian crisis in coastal Myanmar and Bangladesh, depending in part on how intense it gets before crossing the coastline.

Laurin-Whitney Gottbrath contributed to this story.

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