A fierce cyclone tore into India’s coast, killing at least five people, forcing half a million into shelters and threatening to devastate farmland and fishing hamlets.

Cyclone Phailin was expected to remain a “very severe cyclonic storm” — packing dangerous winds of up to 138 mph and gusts up to 167 — into today before steadily weakening as it moves inland in the states of Odisha and Andhra Pradesh.

A few hours before it hit land, the eye of the storm collapsed, spreading the hurricane force winds out over a larger area and giving it a “bigger damage footprint,” said Jeff Masters, meteorology director at the U.S.-based private Weather Underground.

The storm snapped trees and electricity poles and smashed windows in Behrampur, a town in the area where it hit land on Saturday evening.

Rescue workers and soldiers spread out across the region in helicopters and trucks and the full extent of destruction was only expected to become clear after daybreak today.

Some 12 million people were in the path of Phailin, weather and disaster management officials said. It was India’s strongest cyclone since a typhoon killed 10,000 people in the same region 14 years ago. Aid agencies hope better preparation and early warnings will mean far fewer casualties this time.

Satellite images showed a vast spiral-shaped storm covering most of the Bay of Bengal’s warm seas, before it churned inland.

Jagdesh Dasari, a leader in the fishing village of Mogadhalupadu, said police ordered villagers to leave their mud and thatch huts for a school building as night fell. Many on the impoverished coast were reluctant to go, afraid of losing belongings.

“Many people refused to move, had to be convinced, and at times the police had to forcefully move them to safe places,” Home Minister Sushilkumar Shinde said.

In the first reported deaths, four people were killed by falling trees, while another died when the walls of her mud house collapsed. Electricity went out in several towns, including Odisha’s capital Bhubaneswar.

“We are fortunate that we are here … we saved our lives,” said Narayan Haldar, huddled with 1,300 people in an Odisha fishing village storm shelter, built after the 1999 typhoon.

But he complained the government had not provided food. Some shelters were dilapidated and TV images showed crowds standing in the rain outside one overcrowded building.

Large waves pounded beaches and villagers told a television station that surging sea levels has pushed water hundreds of feet inland in low-lying areas. By Saturday afternoon, the sea had already pushed inland as much as 130 feet along parts of the coastline.

The state’s top official, Chief Minister Naveen Patnaik, appealed for calm.

“I request everyone to not panic. Please assist the government. Everyone from the village to the state headquarters have been put on alert,” he told reporters.

The Indian military has put some of its forces on alert, and has trucks, transport planes and helicopters at the ready for relief operations. India’s disaster preparations have improved since the 1999 storm and aid workers praised the precautions taken.

Some 550,000 people were crammed into makeshift shelters including schools and temples, in what the National Disaster Management Authority called one of India’s largest evacuations.

Even before landfall, coconut trees in villages along the coast were bent and broken in the gusting wind. Electrical poles were brought down and roads littered with debris.

Terrified children clung to their mothers as they sought shelter. Most towns along the coast were deserted but some people were still trying to flee in buses and three-wheeled auto-rickshaws just hours before the storm struck.

The size of the storm made extensive damage to property more likely, Shashidhar Reddy, vice chairman of the National Disaster Management Authority told reporters in New Delhi. “Our priority is to minimize loss of life,” he said.

U.S. forecasters had repeatedly warned that Phailin would be immense.

“If it’s not a record, it’s really, really close,” University of Miami hurricane researcher Brian McNoldy said. “You really don’t get storms stronger than this anywhere in the world ever.”

To compare it to killer U.S. storms, McNoldy said Phailin is nearly the size of Hurricane Katrina, which killed 1,200 people in 2005 and caused devastating flooding in New Orleans, but also has the wind power of 1992’s Hurricane Andrew, which packed 165 mph winds at landfall in Miami.

The Indian weather department warned mud houses faced destruction. It said the disruption of power and communication lines and the flooding of railways and roads was likely.

Despite the warnings, some refused to leave their homes.

“I have a small child, so I thought, how will I leave?” asked Achamma, 25, holding her son in Donkuru, a fishing village in Andhra Pradesh, as waves crashed on the beach.