Bangladesh has ordered the evacuation of nearly 500,000 people ahead of Cyclonic Storm Mocha, which was strengthening as it churned over the Bay of Bengal on Friday ahead of an expected landfall this weekend.

The evacuations, which will start Saturday according to The Associated Press, will take place amid warnings from the U.N.'s World Meteorological Organization of a humanitarian crisis at the world's largest refugee camp in the town of Cox's Bazar, Bangladesh, near where the cyclone is forecast to make landfall on Sunday, accompanied by a storm surge, flooding rainfall and damaging winds.

This AccuWeather RealVue™ Enhanced satellite image shows massive Cyclone Mocha over the Bay of Bengal on May 12, 2023.

The neighboring, low-lying nation of Myanmar (also known as Burma) is also expected to sustain significant impacts from Mocha, and officials there were also preparing to evacuate residents, according to the AP. Experts are pointing out that the cyclone could be the worst to impact the country in over a decade.

As of Friday evening, local time, Mocha was centered several hundred miles south-southwest of Cox's Bazar and was classified as a "very severe cyclone," according to the India Meteorological Department (IMD). This means maximum sustained winds associated with the storm were equivalent to that of a Category 2 hurricane on the Saffir-Simpson hurricane wind scale (96-110 mph, or 155-175 km/h).

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AccuWeather meteorologists pointed out that Mocha was a particularly large cyclone, with an expanse of shower and thunderstorm activity that nearly covered the entire diameter of the Bay of Bengal, about 1,000 miles (1,600 km) across.

"Mocha has blossomed into a very dangerous cyclone during the last 24 hours," said AccuWeather Senior Meteorologist Adam Douty. "Some additional strengthening can be expected as the storm moves slowly northeastward into the weekend, with the chance the system can reach 'extremely severe cyclonic storm' status for a time."

Cyclone Mocha's winds on AccuWeather's Wind Flow map Friday evening local time.

An "extremely severe cyclonic storm" packs winds that can reach as high as 135 mph (220 km/h), which is the equivalent of a Category 4 hurricane.

Landfall is expected to take place on Sunday afternoon or evening, local time, near the border of Bangladesh and Myanmar. By then, Mocha may have lost a little wind intensity on its final approach, but major impacts are still expected, according to AccuWeather forecasters.

"A dangerous storm surge is expected to inundate the coastline of northern Myanmar, where the ocean water could rise 10-20 feet (3-6 meters)," said Douty. "The most prone areas to this [threat] will be bays and inlets just to the south of the landfall location."

Flooding will not be limited to areas near the coast, as Douty pointed out that the threat of life-threatening flash flooding from heavy rain will extend well inland across northern Myanmar, southeastern Bangladesh and far eastern India, where the terrain turns mountainous. The ferocious downpours will likely trigger mudslides and landslides, even after the cyclone exits.

Most areas close to the center of Mocha's track are forecast to receive 5-10 inches (125-255 mm) of rain, with 10-20 inches (255-510 mm) likely in the mountainous terrain of northern Myanmar. The AccuWeather Local StormMax™ for rainfall is 25 inches (635 mm). This total could occur in some highly localized areas.

With warnings that the most dangerous cyclone in years was on the way and slated to impact one of the world's most vulnerable and economically disadvantaged regions, officials were preparing on Friday ahead of the expected impacts this weekend.

The U.N. Refugee Agency was preparing for a partial evacuation of a Rohingya camp in Cox's Bazar, where about a million refugees live after fleeing Myanmar in 2017 due to a "military-led crackdown," according to Reuters. The agency was prepping tens of thousands of hot meals and jerrycans, which are used to hold fresh water, Reuters reported.

The camp was still reeling after a devastating fire in March that destroyed shelters and critical infrastructure, according to the AP. The International Rescue Committee was also on the ground there ahead of the cyclone, deploying mobile medical tents.

Rohingya refugees try to salvage their belongings after a major fire in their Balukhali camp at Ukhiya in Cox's Bazar district, Bangladesh, Sunday, March 5, 2023. A massive fire raced through a crammed camp of Rohingya refugees in southern Bangladesh, leaving thousands homeless, a fire official and the United Nations said. (AP Photo/Mahmud Hossain Opu)

Mocha, the first named storm of the 2023 northern Indian Ocean tropical season, could end up being the strongest cyclone to impact Myanmar since 2010, when Cyclone Giri came ashore with winds of over 140 mph (225 km/h), according to NOAA.

Cyclones in this part of the world can prove especially deadly. According to the AP, at least 138,000 people died as Cyclone Nargis spread a storm surge inland across Myanmar in May 2008. More recently, Cyclone Mora killed 194 people in 2017, after impacting Sri Lanka and Myanmar, according to the New York Times.

Even in the wake of Mocha, heavy showers and thunderstorms, which are typically terrain-induced this time of year in this part of the world, will continue through most of next week. Downpours and lightning from any storms will hamper cleanup and recovery efforts in the days and weeks after.

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