Nothing unusual, such spells of heavy to very heavy rain are witnessed every July, says a coy IMD

Waterlogging at S B Barve Road, Kurla, on Sunday. Pics/Sameer Markande

The India Meteorological Department (IMD) on Sunday blamed a "sudden development of intense convective clouds" for its delayed warning on the devastating rainfall in the city on Saturday night and Sunday morning. An IMD official said, "But, there is nothing unusual about this kind of rainfall. Every year, in July and August, the entire Konkan belt receives heavy to very heavy rainfall. We had indicated in our forecast that landslides and mudslides were likely to occur."

Mumbai started receiving heavy to very heavy rainfall from 10.30 pm on Saturday. However, the IMD issued a forecast only at 12.30 am on Sunday, warning that intense to very intense spells of rainfall were "very likely to occur in the districts of Mumbai during the next three hours".

Waterlogging at S B Barve Road, Kurla, on Sunday

An IMD official said, "There was definitely a timely prediction and a red alert was issued on Saturday night. We had indicated it in both our alert [at 12.30 am] and impact-based forecast. However, the situation changed with the development of intense convective clouds over Mumbai on Saturday night, which caused the heavy to very heavy rainfall. This was indicated in our nowcast alert."

The official added, "This kind of weather is likely to prevail for the next five days. Extremely heavy rainfall cannot happen everywhere, only at isolated places."

Meanwhile, the IMD has issued an orange alert for five days, starting Monday. The official said that Mumbaikars can expect heavy to very heavy rainfall over the next few days. "People must remain careful. There is also a risk of inundation when high tide coincides with heavy rainfall."

Also read: Mumbai: Heavy rain gets their goat, traders forced to reduce prices

From yellow to red alert in 3 hours

Even though heavy rain had started pelting the city by 10 pm on Saturday, the Regional Meteorological Centre Mumbai put out a tweet at 10.32 pm stating that "moderate to intense spells of rain" were expected, along with gusty winds, thunderstorms and lightning very likely to occur in Raigad, Mumbai, Thane, Palghar and Ratnagiri within the next 3-4 hours.

It was only at 1 am that the weather department put out a yellow alert stating that there was "heavy to very heavy rainfall at a few places with the possibility of thunder/lightning and gusty winds". Unfortunately, by this time, the intense spells of rainfall were already wreaking havoc across the city.

By 3 am, the IMD had upgraded it from yellow to a red alert.

At 3.30 am, the weather department put out its nowcast warning (finally) stating that "intense to very intense spells were very likely to occur at isolated places" in the Thane, Raigad, Palghar, Mumbai (greater intensity towards the northern part of suburbs) during the next three hours.

BMC blames IMD

The BMC too had put out its first-ever warning tweet, piggybacking on IMD's 12.30 am nowcast warning but by then the loss to life and property was already done. Several civic officials called out IMD's lax forecasting on news channels on Sunday, stating that they did not have enough time to prepare.

City inundated over weekend

Over 200 mm rainfall was recorded in five hours in the limits of the Brihanmumbai Municipal Corporation (BMC) between 11 pm on Saturday and 4 am on Sunday. This led to Vihar Lake overflowing on Sunday.

The highest rainfall of 226.82 mm was recorded by the automatic weather station at Dahisar Fire Station in R North ward. Other rain levels include 218.45 mm in Chembur, 206.49 mm in Kandivli, 202.69 mm in Borivli, 201.93 mm in Fort and 200.4 mm in G South area (Worli).

"Rain has been heavy in the city since the night of Saturday, July 18. It was raining continuously till 4 am on Sunday. All the systems of BMC, 24 divisional offices, the Main Emergency Control Room and 25 Assistant Control Rooms, and the Mumbai Fire Brigade worked continuously through the night. All major and suburban hospitals of the corporation were also instructed to be ready for necessary action," said a civic official.

During the approximately 10-hour heavy rain period, 442.35 crore litres of water was pumped into the sea through BMC's 6 pumping stations, greatly helping in the drainage of rainwater in Mumbai, said officials.

There were 31 waterlogging spots recorded in the city and civic officials claimed the water receded in the morning.

Apart from the three major wall and house collapses that totally killed 32 people, there were eight other collapses, fortunately there were no casualties. The incessant rain caused 13 short circuit incidents killing one person. At nine places there were reports of branches falling.

The Vihar Lake started overflowing on Sunday at 9 am. Last year, it had started overflowing on August 5, at around 10.00 pm.

Transport almost at a standstill Public transport almost halted early Sunday morning leaving many people affected, but normalised later. Railway services were down, but were restored by 11am.

About 24 BEST buses were submerged across the city but by 3pm on Sunday, all had been towed away.

The BEST spokesperson said another 10 buses were stranded due to technical issues and were attended to. According to the the 3.30 pm update on Sunday, roads with bus routes were flooded at 37 locations leading to diversions and detentions.