Vayu, which is now classified as a very severe cyclonic storm, is expected to hit Gujarat state early on Thursday. Authorities are trying to evacuate close to 300,000 people living in coastal areas.
Indian authorities evacuated tens of thousands of people on Wednesday as a severe cyclone in the Arabian Sea approached the western state of Gujarat, lashing the coast with high winds and heavy rainfall.
Cyclone Vayu, named after the Hindi word for wind, was poised to glance the Gujarat coast on Thursday afternoon as India's second major storm of the season.
Winds gusting up to 180 kilometres (112 miles) per hour were forecast and a storm surge up to 2 meters (6.5 feet) above astronomical tides, which would inundate low-lying areas, according to the India Meteorological Department.
K Sathi Devi, the New Delhi-based government scientist in charge of monitoring the cyclone, said a low-pressure system over the ocean was causing water to "get piled up."
When the storm makes landfall, so will the accumulated sea water, she said, threatening to flood roads and uproot trees, contaminate drinking water supplies, and disrupt communications and power supplies.
Vayu was forecast to skirt the coast as it travelled west toward Pakistan, retaining its intensity for as long as 12 hours as it straddled land and sea.
"Very strong wind will likely remain for a longer period," said R.K. Jenamani, another government scientist. "It's a very unique kind of system."
Warnings and preparations
In the ancient city of Dwarka, where many Hindu pilgrims travel every year to pray at a temple considered the centre of Lord Krishna's kingdom, a rescue worker from India's National Disaster Response Force warned children to leave the beach.
After India's home minister Amit Shah held a meeting on Tuesday with government and military officials, the air force airlifted 40 National Disaster Response Force rescue and relief teams to the western coast.
Both Shah and Prime Minister Narendra Modi hail from Gujarat.
Modi said on Twitter that he had "been constantly in touch with state governments" and that he was "praying for the safety and wellbeing" of all those affected.
By midday, rescue teams had begun evacuating more than a quarter of a million people in towns and villages likely to bear the brunt of the storm.
The scale of the possible damage when Vayu makes landfall wasn't immediately clear, but meteorologists predicted the destruction of thatched homes, flooding of escape routes and widespread damage to crops. They recommended that authorities focus evacuation efforts on residents of makeshift housing, from beachside huts to urban slums.
Authorities appeared to have taken some cues from Cyclone Fani, which hit India's eastern coast on the Bay of Bengal in May, killing 34 people in India and 15 in neighbouring Bangladesh.
Authorities in the eastern state of Odisha, where Fani made landfall, were praised for precautionary measures — including evacuating more than a million people — that likely prevented a much higher death toll.
In India's financial capital of Mumbai, police tweeted that because of the high winds, heavy rainfall and lightning expected from Vayu, people "should not venture into sea and should keep safe distance from shoreline."
Gujarat's chief minister, Vijay Rupani, requested on social media that tourists leave coastal areas by Wednesday afternoon.