Cyclone Phailin, the most powerful storm to take aim at northeastern India since 1999, forced the evacuation of tens of thousands along the Bay of Bengal coastline as it threatened to flood escape routes, disrupt rail service and cut off power for weeks.

Phailin, which means “sapphire” in Thai, has winds of 135 mph and was expected to make landfall about 6 p.m. local time Saturday, according to L.S. Rathore, director-general of the India Meteorological Department. The U.S. Navy’s Joint Typhoon Warning Center in Hawaii estimated Phailin’s top winds at 161 mph, a Category 5 on the U.S. hurricane scale, which is different than the one used by the rest of the world. Hurricane Andrew in 1992, was a Category 5 storm.

“The storm has the potential to cause huge damage,” Rathore said. “We don’t contemplate it will further intensify. It will remain as a very severe cyclonic storm.”

Phailin sent at least 64,000 people fleeing from their homes and forced ships out of its path, and is expected to cause crop and infrastructure damage. Twenty-six of the world’s 35 deadliest tropical cyclones, the storms that include hurricanes and typhoons, have occurred in the Bay of Bengal, according to Jeff Masters, founder of Weather Underground in Ann Arbor, Mich.

“It’s going to cause pretty complete devastation on the coast where it hits,” Masters said by telephone. The storm weakened slightly as it grew larger but had begun to strengthen again. Masters said it was likely that Phailin would lose some strength before going ashore, probably in the Odisha region, as the equivalent of a Category 4 storm, the second-strongest on the five-step Saffir-Simpson Scale.

Andrew, which hit southern Florida, had top winds of 174 mph and was a 150 mph storm when it made landfall, according to AccuWeather in State College, Pa.

Paradip Port Trust, India’s biggest dry bulk cargo facility, sent all its ships to sea and shut down operations, spokesman Prakash Chandra Mishra said by phone. The National Disaster Management Authority dispatched a 1,500-person rescue force to Odisha and Andhra Pradesh states, while the Indian air force said it sent two IL-76 airlift teams and was committing two C-130J Super Hercules planes.

Andhra Pradesh’s chief minister, Kiran Kumar Reddy, urged citizens in low-lying areas to move to safer ground.

“We are prepared for the worst,” Pradipta Kumar Mohapatra, special relief commissioner of Odisha, said by phone from the state capital of Bhubaneswar.

— Bloomberg News