North India Deluge 2023: Rainfall during July 1-10 broke multiple records

July 1 through July 10 was a record-breaking period for several parts of the country during monsoon 2023. Delhi, Chandigarh and Himachal Pradesh surpassed several records even as parts of the country remained dry. 

At least some regions of all 36 states/Union Territories experienced excess and large excess rainfall from July 1 through July 10, 2023. Of these, 29 states/UTs recorded large excess rainfall, exceeding the normal by 61 per cent going up to 10,000 per cent. 

However, at the end of this period, the rains in 20 states were below normal even as 14 states received excess or large excess rainfall.

Also read: North India Deluge 2023: A water plan addressing urban floods can pull Chandigarh out of troubled waters

The IMD categorises rainfall between -19 per cent and 19 per cent as “normal”, between -59 per cent and -20 per cent as “deficient” and between -99 per cent and -60 per cent as “large deficient” on its index.

Moreover, rainfall between 20 and 59 per cent is considered “excess” rainfall and over 60 per cent above the average mark is “large excess”.

On July 10, 2023, over 39 per cent of Indian states received large excess rains, which were devastating due to their intense and extreme nature, especially in states of the North-Western region. In contrast, 56 per cent of the states were rain deficient.

Despite torrential rains in northwestern India during July 8-10, large parts of the country are still facing a rainfall deficit. Southern Peninsular states like Kerala and Karnataka are rain deficient and remained dry as per the India Meteorological Department data for June 1- July 10, 2023.

A closer look at the rainfall trends showed the intense rains were first recorded in Goa in the Central region on July 3, 2023. The state had received over 186 per cent of its normal rain on  July 3, 2023, followed by Meghalaya (excess of 121 per cent) and Bihar (excess of 84 per cent) in East and North East. 

Thereafter, on July 4, 2023, seven states in the country recorded large excess rains. Of these, six belonged to the South Peninsular region: Puducherry, Lakshadweep, Andhra Pradesh, Tamil Nadu, Kerala and Karnataka.

Also read: North India Deluge 2023: Heavy rains in Nepal cause erosion downstream in Bihar; hundreds displaced

At the same time, July 6, 2023 can be considered a landmark during the period for several reasons. Firstly, if the geographical spread of excess and large excess rainfall is considered, 22 states recorded rains that were either excess or large excess on the day. 

On the same day, 16 states in all four regions — North West, Central, South Peninsula, East and North-East — recorded large excess rains. 

The excess rainfall varied to 1,600 per cent from 61 per cent across the states, with Chandigarh facing the worst of it. The city received 20.4 millimetres (mm) of rains as compared to normal rains of 1.2 mm on this day. 

While excess rains in the month of July are normal, the intensity of rains and the devastation caused by these rains have been unprecedented

On July 9, 2023, 13 states/UTs recorded large excess rainfall in the range 65 per cent to 10,000 per cent. Several records of extreme rains were broken across northern states/UTs, which included Chandigarh, Delhi and Himachal Pradesh.

Rainfall in Punjab exceeded the normal rains by 1,100 per cent on the day. A deep-dive into districts revealed that all 22 districts received excess or large excess rainfall. 

But the rainfall received in 12 of these districts was more than the normal by 1,200-7,650 per cent.

Fazilka received over 7,650 per cent of its normal rain on July 9, 2023, followed by Faridkot (3,355 per cent) and Rupnagar (3,156 per cent) . These district-level insights indicate that planning to adapt to such extreme events needs to consider “regional-level estimates,” which is beyond the “average data on rainfall”.

The rains in the state exceeded the normal by 532 per cent on July 6, 2023 and was 109 per cent more than the normal by over 100 per cent. This is in contrast to the years 2021 and 2022, when the state had deficit rains around the same time, as per government data. 

The state is flooded at present and at least 150 rural roads and 10 small bridges have been damaged since July 7, 2023 as per the initial assessment by the state Public Works Department (PWD), said a media report. 

Record breaking rainfall

On 4 out of 8 days between July 3 and 10, 2023, Chandigarh recorded large excess rains as per the IMD. Of these, the rains on July 9, 2023 were more than normal by over 6,800 per cent.

Chandigarh received 290.9 mm of rain on the day compared to normal rains of 4.2 mm.

Thus, the rainfall in July 2023 in Chandigarh was the highest-ever and broke the 23-year record for the highest rainfall in July since the year 2000. On July 18, 2000 the city recorded 262 mm rainfall and was the highest as per record. 

On July 10, 2023 too, the rainfall in the city exceeded the normal by over 1,200 per cent . As a result, the city with deficit rains in the monsoon period from June 14, 2023 to July 5, 2023 had surplus extreme rains by July 10, 2023.

The cumulative rains received by the city between June 1 and July 10, 2023  is now more than the normal by over 180 per cent. On July 10, 2023, the cumulative rains received by the city was 636 mm, an increase from the normal rain of 225.1 mm during this period. 

Delhi received excess and largely excess rain on five out of eight days between July 3 and 10, 2023. On July 9, 2023 the city recorded 221.4 mm of rains and had exceeded its long-period average of 209.7mm for the month of July 2023. 

The heavy rains on July 8 and 9, 2023 in the city broke 40-year-old record, as acknowledged the IMD in a tweet.

“New Delhi (Safdarjung) recorded 3rd highest 24-hour rainfall (for the month of July) on July 8-9, 2023, since 1958,” tweeted the IMD on July 9, 2023 at 10.38 am. 

Five highest records of 24-hour rainfall in July for New Delhi (Safdarjung base station) during 1958-2023

Himachal Pradesh had deficit rains from July 3-5. After it, the state also bore the brunt of extreme rains. 

About 30 per cent of the total rainfall the state gets during the monsoon season (June to September) was received in just four days (July 7-10, 2023), which is unprecedented, records showed. 

The state received heavy to very heavy rainfall on these days, which exceeded the normal rainfall by 1000 per cent on July 9 and 10, 2023.

Also read: North India Deluge 2023: Development projects compounding destruction in Himachal Pradesh, say experts

On July 9, 2023, all 12 districts in Himachal Pradesh had recorded large excess rainfall. Lahaul and Spiti received over 3,640 per cent of its normal rain on July 9, 2023, followed by Una (2,168 per cent) and Chamba (1,250 per cent)

In fact, the rainfall during these two days broke 52 to 96 years’ record in Shimla, Solan and Una districts as per the Shimla meteorological department quoted in news agency Press trust of India and other media reports.

The state remains the worst-affected and lost the maximum number of lives. Floods and landslides have so far claimed at least 64 deaths as per the government estimates as of July 11, 2023. However the human toll is likely to be more, if media reports are considered.

Rainfall records broken in Himachal on July 9-10, 2023

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