Delhi rains: Several weather stations record over 100mm rainfall overnight; ‘yellow alert’ in place

Multiple weather stations in Delhi recorded over 100mm of rainfall till Thursday morning as Delhi continued to receive light to moderate showers overnight following a convergence of thunderclouds over NCR on Wednesday evening.

The initial extremely intense rainfall – over 50mm per hour – led to waterlogging in most parts of the city, disrupting air traffic as well. Weather officials said though there was a drop in intensity after 8:30 pm on Wednesday, rain continued to batter most parts of Delhi till about 2.30am, before clouds began to clear up.

Forecasts by the India Meteorological Department (IMD) show that Delhi is likely to experience scattered drizzles to light rain in some parts over the next few hours, with a yellow alert in place for the rest of Thursday.

IMD data from 8.30am on Wednesday till 5:30 am on Thursday showed several stations, including Safdarjung – the station that is representative of Delhi’s weather – had received ‘heavy’ rainfall. The IMD classifies rainfall as ‘heavy’ when it is over 64.4mm in a 24-hour period.

Till 5.30am on Thursday, Safdarjung had recorded 107.6mm rainfall; Palam 68.3mm; Delhi University 104.5mm and Pusa – the station nearest to Old Rajender Nagar, where three students died last Saturday after rainwater entered a basement – recorded 86mm.

It was 112.5mm at Najafgarh and 147.5mm at Mayur Vihar. Narela recorded moderate rainfall (39.5mm) and so did Pitampura (45.5mm).

IMD’s three-hourly rainfall data showed that after the city received 79.2mm rainfall between 5.30pm and 8.30pm on Wednesday, the next three hours till 11.30pm saw only 15.2mm of rain. Between 11.30pm and 2.30am, another 13.2mm was recorded. In the next three hours, no rainfall was recorded. A similar trend was seen at other stations, with the maximum intensity recorded between 5.30pm and 8.30pm, followed by incessant but light to moderate rainfall over the next six hours till 2.30am.

No rainfall was recorded at any weather station between 2.30am and 5.30am.

The weather department classifies rain as ‘light’ when it is 10mm per hour; 10-20mm per hour is ‘moderate’; 20-30mm is ‘intense’; 30-50mm per hour is ‘very intense’ spell; 50-100mm per hour is ‘extremely intense’ spell and over 100mm per hour is a ‘cloudburst’. With 89.5mm recorded at Mayur Vihar between 6.30 pm and 7.30 pm on Wednesday, the IMD said this was close to a ‘cloudburst’.

The Delhi Traffic Police also issued an advisory for early morning commuters, asking them to avoid Rohtak road due to heavy waterlogging and potholes.