India set for wetter September; IMD warns of flash floods and landslides

New Delhi: India is bracing for above-normal rainfall in September, the India Meteorological Department (IMD) said on Sunday, capping a monsoon season already marked by extreme weather events, floods, and landslides across multiple regions.

The IMD’s latest forecast indicates that the country is likely to receive more than 109 per cent of the long-period average (167.9 mm) for September. Director General Mrutyunjay Mohapatra cautioned that this could intensify risks in vulnerable states.

“Many rivers originate in Uttarakhand. So, heavy rainfall means many rivers will be flooded and it will impact cities and towns downstream,” Mohapatra said during an online briefing. He added that flash floods and landslides could disrupt life in the hill state as well as in Delhi, south Haryana and north Rajasthan. Heavy showers are also expected in the upper catchment of the Mahanadi river in Chhattisgarh.

The IMD chief noted that September rainfall has shown a rising pattern since the 1980s, with exceptions in years such as 1986, 1991, 2001, 2004, 2010, 2015 and 2019. One reason, he explained, is that the normal withdrawal of the southwest monsoon from Rajasthan has shifted from September 1 to September 17.

“September is a transitional month when the season moves towards the post-monsoon phase. With the withdrawal delayed, the chances of interaction between the monsoon and western disturbances rise. The frequency of these disturbances also increases as winter approaches,” Mohapatra said.

India received 743.1 mm of rainfall between June 1 and August 31, about six per cent above the long-period average of 700.7 mm. All three months of the season have reported excess rainfall.

In June, the country recorded 180 mm, nine per cent above normal. July saw 294.1 mm, five per cent higher than average, while August brought 268.1 mm, also around five per cent above normal.

Northwest India has stood out, experiencing an unusually wet season. Rainfall in June was 111 mm, 42 per cent above normal. July recorded 237.4 mm, 13 per cent above average. In August, the region received 265 mm against a normal of 197.1 mm, an excess of 34.5 per cent—the highest August rainfall since 2001 and the 13th highest since 1901.

Cumulatively, northwest India received 614.2 mm of rainfall between June and August, around 27 per cent higher than the normal of 484.9 mm.

South Peninsular India also saw unusually high rainfall. The region recorded 250.6 mm in August, about 31 per cent above normal, making it the third highest for the month since 2001 and the eighth highest since 1901. From June to August, it registered 607.7 mm against the normal of 556.2 mm, a surplus of 9.3 per cent.

The heavy rains have been accompanied by severe weather events. Punjab endured its worst floods in decades, with overflowing rivers and breached canals inundating thousands of hectares of farmland and displacing lakhs of residents.

In Himachal Pradesh, Uttarakhand, and Jammu and Kashmir, repeated cloudbursts and flash floods triggered landslides and washed away bridges and roads. Jammu saw major flooding, while towns in Himachal and Uttarakhand faced extensive damage to life and property.

Between July 28 and August 14, active western disturbances caused heavy rainfall in the western Himalayas, leading to a flash flood and landslide in Uttarkashi on August 5, and riverine floods in Uttar Pradesh and Bihar.

Extremely heavy rainfall events were reported in multiple regions later in August. East Rajasthan experienced intense showers from August 22 to 24, Punjab and Haryana from August 23 to 26, and Jammu and Kashmir from August 23 to 27. Konkan and parts of Maharashtra also reported exceptionally heavy rain on August 20, while Telangana was hit on August 28.

According to Mohapatra, interactions between monsoonal low-pressure systems and western disturbances have played a crucial role in the unusual rainfall patterns this season. Typically, low-pressure systems from the Bay of Bengal travel through Odisha and central India. But this year, many shifted course, moving across Gangetic West Bengal, Jharkhand, and Uttar Pradesh, or through Andhra Pradesh, south Odisha, Chhattisgarh and Telangana.

“Northwest India saw three such active interactions in August, which led to incidents in Dharali (Uttarakhand), Kishtwar (Jammu and Kashmir), Jammu and Mandi (Himachal Pradesh),” Mohapatra explained.

The IMD has not identified an increasing trend in cloudburst events overall, but a study by the Indian Institute of Tropical Meteorology points to a rise in so-called “mini cloudbursts”—defined as rainfall of 5 cm or more in an hour. As the season enters its final phase, officials are monitoring regions at risk of renewed flooding and landslides. The IMD has warned that the coming month may bring more extreme rainfall, particularly in the western Himalayas and adjoining plains.

With rivers already swollen and soils saturated in many areas, further heavy rainfall in September could worsen the damage seen over the past three months.