Cyclone ‘Nisarga’ weaker, but it still carries significant danger; ‘low-lying areas could get flooded’

♦ Sustained winds at 111 kmph
♦ Avoid travel, stock up on essentials
♦ Low-lying areas could get flooded
♦ City could experience power outage


Is Mumbai in the throes of “the most serious cyclone the city has experienced in its modern history”? Even though the IMD, on Monday, has stated that Mumbai and its adjoining areas will receive heavy rainfall on June 3 – as the deep depression over east-central and adjoining southeast Arabian Sea will intensify further into a cyclonic storm ‘Nisarga’ over east central Arabian Sea in the next 24 hours – the question about the intensity with which the storm will hit the city still looms large.

For a little more than a week, Adam Sobel, a scientist at Columbia University who studies extreme weather and climate change, has been putting out alerts on Twitter, tracking various models, about the cyclone formations over the Arabian Sea, and how it could possibly make landfall a little north of Mumbai with high intensity.

Sobel is well-versed with the city and the risks a cyclone poses; he and his colleagues have even authored a paper looking at Mumbai’s cyclone preparedness, which, according to author Amitav Ghosh, explores how “the city remains completely unprepared for such a disaster.” In an email interview with Mirror, the author of Storm Surge: Hurricane Sandy, Our Changing Climate, and Extreme Weather of the Past and Future, tells us that even though the intensity of the storm for now has reduced, the city is still very much at risk.

How badly do you think the cyclone will hit Mumbai?


The IMD is now issuing track and intensity forecasts for this storm. They are the official forecast agency and their predictions are state of the art; I am not making my own forecast, only providing some interpretation. The latest IMD track takes the storm right over Mumbai on Wednesday as a Severe Cyclonic Storm (SCS) with 60 knot (111kmph) maximum sustained winds. In the US system, this would be a strong Tropical Storm, not quite a Hurricane (but close).

The track forecast is bad for Mumbai, but the intensity forecast is good relative to what it was 12 hours ago, when some models were predicting that it could become much more powerful. Those models have backed off now. So the chances of a worst case scenario, with, for example, a very extreme storm surge, is now reduced quite a bit. However, an SCS with 60 kt (111 kmph) winds can still be dangerous, so people should still be prepared for both high winds and flooding. And there is still time for things to change, so everyone in the area should monitor the forecast closely.

What makes Mumbai so vulnerable to such weather conditions?
And how has the city failed to prepare for such situations?

The city is completely exposed to the sea, with many flood-prone low-lying areas. Some of the most vulnerable areas are informal settlements such as Dharavi, which is also heavily affected by the pandemic now. But also many upscale areas like Marine Drive are very exposed.

Mumbai has not been affected by cyclones in its modern history. The city has experienced severe floods of course, in 2005 and more recently in 2017 and 2019. But these were not due to cyclones. The city has not had a serious cyclone landfall at least since the 19th century, perhaps longer (we only have good data since 1891 and there has not been a Mumbai cyclone of any significance during that time). In recent years, many new tall buildings have been built, and I don’t know to what extent they have been designed for the strong winds of a cyclone. Winds at the tops of such buildings will be stronger than at the ground. I don’t have any comment on whether the city has “failed” to prepare. The government documents I have been able to find, however, do not show detailed plans for the event of a strong cyclone in Mumbai.

What precautions do you advise the city should be undertaking right now?

People should be prepared to avoid travel; stock up on necessary supplies; there could be loss of power, etc. Please follow the advice of local leaders and emergency managers. I hope largescale evacuation will not be necessary, but in the case of flooding, it might be necessary to get out of the lowest floors of some buildings in low-lying areas.

Why is there a lag in the forecast by IMD informing us of the intensity of the storm?

There is not a “lag”, but formal cyclone forecasts and warnings don’t begin until the storm has formed, which it only did (reaching Depression stage) in the last 12 hours or so. This is true not just of IMD but most forecast agencies around the world. It poses problems when a storm forms close to land so that there is a short time between formation and landfall.