The storm strengthened further on Sunday morning as it headed toward land, in an area that is home to the world’s largest refugee camp.
A storm forecast to be the strongest to hit Myanmar in more than a decade is expected to make landfall near the Bangladesh border on Sunday, raising the prospect of a major humanitarian disaster.
The storm, Cyclone Mocha, formed over the southern Bay of Bengal on Thursday and has been drenching western Myanmar as it churned northeast, with heavy rain, strong winds and storm surges forecast to continue through Sunday, according to the Global Disaster Alert and Coordination System.
On Sunday morning, maximum sustained winds reached 160 miles per hour, with gusts surpassing 180 miles per hour, according to the Joint Typhoon Warning Center, placing the storm as a Category 5 hurricane. This is the highest rating on the Saffir-Simpson Scale and indicates potential for catastrophic damage.
Waves are expected to reach up to 20 feet off the Rakhine coast, according to the Myanmar Ministry of Foreign Affairs.
Myanmar and Bangladesh began deploying thousands of volunteers and ordering evacuations from low-lying areas, Agence France-Presse reported, in a region that is home to some of the world’s poorest people, who are especially vulnerable to increasingly severe weather events.
In Myanmar, the risk of devastation is compounded by its ongoing civil war, which has displaced some 1.8 million people across the country, with the region south of the Bangladesh border being an active fighting zone and home to several large refugee camps.
There was high confidence among forecasters with the Joint Typhoon Warning Center that the center of the storm, and worst part of the cyclone, will most likely move ashore near Sittwe, Myanmar, in Rakhine State. Sittwe residents have evacuated the city.
Because of the storm’s counterclockwise flow, the worst and most damaging conditions will most likely be at the landfall location and just to the south of where the eye comes ashore. However, damaging tropical storm-force winds, 39 miles per hour or higher, will extend more than 180 miles from the center.
Bangladeshi authorities have instructed fishing boat operators in the Bay of Bengal to stay close to shore.
Cox’s Bazar, the Bangladeshi city that is home to the world’s largest refugee encampment, is bracing for the weather. Muhammad Shaheen Imran, a district official, said that the city had prepared more than 550 shelters to accommodate evacuees.
More than a million Rohingya people live in the sprawling camps.
The Explosive Ordnance Risk Education organization in Myanmar has also issued a warning to the public regarding the hazards posed by land mines and unexploded ordnance during the impending storm.
The World Food Program has secured enough food to provide for 400,000 people in Rakhine State and neighboring areas for a month.
“Cyclone Mocha is heading to areas burdened by conflict, poverty, and weak community resilience,” said Sheela Matthew, the deputy country director for the W.F.P., in a statement. “They simply cannot afford another disaster.”
As the storm approaches the coast, the cyclone should weaken slightly before making landfall. Despite this weakening, winds of this speed can create devastating to catastrophic damage, according to the National Hurricane Center.
With a storm of this intensity, storm surge — the bulge of water that is pushed with the winds as a storm nears the coast — will also be a major concern near the cyclone’s landfall and to the south of it.
Storm surge is often the greatest threat to life and property, according to the Hurricane Center. Forecasters with the India Meteorological Department believe an eight- to nearly 10-foot surge is possible.
After landfall, the storm will quickly dissipate over Myanmar’s rugged terrain.
Mocha looks likely to be the strongest storm to make landfall in Myanmar since Cyclone Giri, which in 2010 packed winds of 143 m.p.h., according to the National Oceanic and Atmospheric Administration’s historical cyclone tracks. That storm killed at least 45 people in Myanmar.
Cyclones are highly destructive. The term “cyclone” refers to a type of tropical cyclone — the umbrella term for all such storms, like hurricanes and typhoons — that forms in the Bay of Bengal or the Arabian Sea, both located in the northern Indian Ocean.
Scientists say that climate change has helped intensify storms because the unusually warm ocean temperatures provide more energy to fuel them.
Cyclone Mocha comes as a deadly heat wave has been searing Southeast Asia for weeks. In April, Dhaka, the capital of Bangladesh, hit 105.1 degrees, its highest temperature in six decades.
The Bay of Bengal, in the northeastern part of the Indian Ocean, has had a long history of major storms.
In 2008, Cyclone Nargis became the second-deadliest tropical cyclone on record and the deadliest in Myanmar, killing more than 135,000 people. In 2007, Cyclone Sidr struck Bangladesh, killing more than 3,000 people.
Saif Hasnat contributed reporting from Dhaka, Bangladesh.