The India Metrological Department (IMD) has issued a red alert for places like Bharuch and Valsad as parts of Gujarat continue to be lashed by rain. Since August 25, heavy rains and floods have killed at least 40 people and displaced over 55,000 people in 25 districts.

The highest rainfall (156 mm) was recorded in Valia in Bharuch between 6 am and 6 pm on Tuesday, followed by Netrang with 127 mm, Umarpada in Surat with 105 mm, Valsad with 104 mm and Jotana in Mehsana with 95 mm.

A helicopter of the Indian Coast Guard, which has deployed four ships and two aircraft for rescue operations, was deployed to evacuate an injured crew member of a tanker off the coast of Porbandar that plunged into the sea after a hard emergency landing late on Monday night. The bodies of two people on board the Dhruv Advanced Light were recovered. A diver was rescued earlier, while the search for the helicopter pilot continued late on Tuesday night.

The IMD said heavy to light rains were expected till the weekend, while power outages continued in over 15,000 villages. Cyclone Asna aggravated the flood situation in Gujarat.

A study by the Machine Intelligence and Resilience Laboratory (MIR Lab) at the Indian Institute of Technology Gandhinagar (IITGN) found that in 12 of Gujarat’s 33 districts, rainfall in one day exceeded the 10-year return period – a statistical measure used to measure the frequency of such extreme weather events.

In districts such as Morbi and Dwarka, rainfall exceeded the 50-year threshold, an intensity that normally occurs only once in half a century. Seventeen districts recorded rainfall exceeding the 10-year threshold on two days. Jamnagar, Morbi and Devbhumi Dwarka recorded rainfall above the 50-year threshold. On three days, 15 districts reported rainfall exceeding the 10-year threshold. Districts including Jamnagar and Dwarka exceeded their expected rainfall amounts.

The pattern of simultaneous extreme events affecting multiple regions simultaneously poses a major challenge for emergency response. Rescue, relief and evacuation operations are becoming increasingly difficult with scarce resources, underscoring the need for scalable emergency response strategies to manage the complexity of large-scale weather events.

Udit Bhatia, principal investigator at MIR Lab, called for an understanding of the nuances of urban flooding. “The level of detail of the available data may not fully capture the specifics of urban flooding, which is often the result of short-term, heavy rainfall that overwhelms urban drainage systems.”

Bhatia added that sustained rains can waterlog the soil during the initial rains, leading to increased surface runoff during subsequent rains. He said this runoff worsens flooding, especially in urban areas where drainage systems are either inadequate or compromised.

The IITGN study cites Vadodara as a good example of this phenomenon, as it experienced severe flooding despite three-day rainfall, which corresponds to a return interval of less than 10 years. This suggests that while the rainfall was not unprecedented, the flooding was likely exacerbated by factors such as extensive urban development in flood-prone areas, changing land elevations, and clogged drainage systems as a result of rapid urbanization.

“The repeated occurrence of such unusual weather events on the west coast of India highlights the urgent need to rethink urban planning and infrastructure resilience. As rapid urbanization continues to alter regional and local hydrology and place greater stress on drainage systems, it is critical to incorporate hydrological considerations into urban development strategies,” the study said. “Addressing these challenges is essential to reduce the risks associated with increasingly frequent and severe weather events and ensure that cities are better prepared for the impacts of future storms.”