Mumbai rain updates: Why live alerts were delayed; watch video

Sunil Kamble, head of the Regional Meteorological Centre in Mumbai, at Colaba, on Thursday. Pic/Anurag Ahire

Following complaints about delayed weather alerts on Wednesday, India Meteorological Department (IMD) officials said that it is not their responsibility to disseminate extreme weather warnings to the public. Instead, they send such alerts to district and city-level disaster management units tasked with informing the masses.

Sunil Kamble, head of the IMD's Regional Meteorological Department, stated, "We are responsible for issuing weather forecasts and warnings about developing systems. However, it is not our role to directly send extreme weather alerts to the public via messages. We provide this information to city and district-level disaster management cells, and it is their responsibility to disseminate the alerts to the public. The IMD has never had a system in place for directly messaging the public."

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Sunil Kamble, head of the Regional Meteorological Centre in Mumbai, at his Colaba office on Thursday. Pics/Anurag Ahire

There had been allegations that on Wednesday that the IMD issued a red alert late, sparking confusion across the city. Initially, an orange alert had been in effect, but it was upgraded to a red alert only after heavy rain and thunderstorms had already started.

BMC sources said due to the dynamic nature of the weather, rainfall often doesn't occur despite the civic body receiving alerts indicating that it will. They added that the corporation takes the necessary precautions before sending alerts to the public to avoid creating unnecessary panic, which can affect day-to-day life. Despite repeated attempts, Mahesh Narvekar, the director of the Brihanmumbai Municipal Corporation (BMC) disaster control cell, could not be reached for comment.

Weather patterns

Emphasising that Mumbai, classified as a heavy rainfall zone, regularly faces such challenges, Kamble said, "Our monsoon season spans from June to September. During these four months, various weather systems - such as offshore troughs, depressions or upper-air cyclonic circulations - affect the intensity of rainfall. These systems bring heavy, moderate, or light rains depending on their formation. Once these systems weaken, rainfall intensity decreases. For Mumbai, an average cumulative rainfall of around 2,300 mm is considered normal for the monsoon season. This year, we are already 500 mm to 600 mm above that mark."

Kamble added, "Wednesday's heavy rainfall was caused by an upper-air cyclonic circulation over central India, with its influence extending to north Maharashtra, coupled with an offshore trough over the region. This resulted in heavy to very heavy rainfall. Historically, a downpour of 300 mm or more in September is not unusual - it's quite typical for this time of year. In fact, we've experienced more intense weather systems than what we saw on Wednesday."

According to Kamble, the rainfall intensity has now subsided, and the IMD is closely monitoring the situation. "The intensity of the rain will begin to taper off by Friday morning unless there are changes in the weather system." The IMD issues a red alert when rainfall of 200 mm or more is expected within 24 hours, while an orange alert is issued for lower amounts. "We also monitor the vertical extent of clouds using Doppler radar. If the cloud height exceeds 10-15 km, the rainfall intensity in that area increases, and we issue flash flood alerts. However, we never issue cloudburst warnings. A cloudburst occurs when over 100 mm of rain falls within an hour, leading to localised flooding," Kamble explained.

Rumour worries

Kamble also expressed concern over the spread of false weather alerts and exaggerated claims on social media. "We have no control over rumours. Despite access to credible information, people often rely on posts from random individuals instead of trusting the forecasts issued by trained meteorologists and scientists who rigorously analyse satellite images and radar data," he said.

He added, "Weather systems are dynamic and can change rapidly. Meteorologists often have differing opinions, so we consult and reach a consensus before issuing any alerts or forecasts. Our forecasts are based on multiple observations and analyses conducted daily. In contrast, social media posts lack accountability, whereas we have a responsibility to provide accurate forecasts." As per the expert, monsoon withdrawal for the city and state is expected on October 5 and 10 respectively.

‘Easy to criticise'

Kamble emphasised the complexity of issuing accurate weather forecasts, stating, "It's easy for people to criticise, but forecasts must be verified and re-verified before being released. We follow strict protocols and make observations daily to ensure accuracy."