Uttarakhand has seen unusual rainfall episode in the month of October 2021. The extreme rains during October 17 to 19 across the state and particularly at several places in districts under Kumaon division have been termed as highest rainfall in the recorded history as per Meteorological Circle (MC), Dehradun. This account is an attempt to document the historical rainfall events caused by combination of low pressure and western disturbance (WD) weather phenomena.
October 16-17, 2021
This year, the south west monsoon covered the state on June 13 about 10 days earlier and retreated by October 8, after a week’s delay. Just day before the heavy rainfalls, several districts under Garhwal and Kumaon divisions witnessed less than normal rainfall. Overall the state recorded 7 mm rains against the normal average of 19 mm.
District wise 24 hours rainfall for 16-17 October 2021.
|Districts||Actual (mm)||Normal (mm)||Districts||Actual (mm)||Normal (mm)|
Rains on October 17-18, 2021
The heavy rainfall spell started in afternoon hours of October 17 and till 08:30 am of October 18, rainfall at 38 stations including AWS, Automated Rain Gauge (ARG) and Manual Observatory (MO) by State government and Indian Meteorological Department (IMD) in 7 districts recorded equal or more than 70 mm of rains according to the Daily Rainfall Report by MC, Dehradun and independent meteorologist, weather bloggers.
24 hours rainfall (≥70 mm) from 08.30 am to 08:30 am on October 17-18.
|AWS/ ARG / MO||Rains (mm)||AWS/ ARG / MO||Rains mm||AWS/ ARG / MO||Rains (mm)||AWS/ ARG / MO||Rains (mm)|
Apart from this, Badrinath registered 101 mm and Kedarnath 45 mm rains in past 24 hours which is not mentioned by MC, Dehradun report. The report has mostly mentioned rainfall amount in round figure with +/- 5mm margin. It misprinted Berinag rainfall figure as 69 cm instead of 6.9 cm.
The data shows extremely heavy rains (>20.44 cm) were recorded at 3 stations, very heavy rains (between 11.56 to 20.44 cm) at 11 sites and heavy rains (between 6.45 to 11.55 cm) at 23 locations from 8.30 am to 8.30 am on October 17-18.
The 24 hours district wise rainfall figure in millimeters (mm) by IMD for the duration is given in table below. According to this, Champawat district reported very heavy rainfall, while US Nagar and Nainital recorded heavy rainfall in 24 hours.
District wise 24 hours (October 17-18) and cumulative rainfall till October 18, 2021
|24 hours rainfall||17-18 Oct. 2021||Cumulative Rainfall||1-10 Oct. 2021|
|SN||Districts||Actual (mm)||Normal (mm)||%Dep.||Actual (mm)||Normal (mm)||%Dep.|
Rains on October 18-19, 2021
The excessive rains continued for second day across 10 districts in the state on October 18. The information shared by independent weather experts Navdeep Dahiya and Shubham Yadav tracking Uttarakhand rainfall episode closely shows that in the first 6 and 12 hours of the day several station recorded extremely heavy to very heavy rainfall. All the 6 districts in Kumaon division again received very heavy to extremely heavy rainfall. At 2 sites it is termed highest rainfall in recorded history.
|08:30 am to 2:30 pm||Champawat (18 cm) Pancheshwar (16.7 cm)||Very heavy to Heavy|
|07:00 am to 02:00 pm||Lansdown (16.6 cm), Satupuli (15.2 cm), Kotdwar (11.6) Nainital (9.0 cm) Shama (8.6 cm)|
|8:30 am to 05:30 pm||Muketeshwar 10.3 cm (0.4 cm less of 10.66 cm all time high rainfall of October 06, 2009)||Heavy|
|8:30 am to 08:30 pm||Jeolikot (26.05 cm), Nainital (24.90 cm), Bhimtal (20.1 cm) Hldwani (13.4 cm)||Extremely heavy|
|8:30 am to 09:00 pm||Kedarnath 12.4 cm||Very heavy|
As per Bikram Singh, Director, MC Dehradun Mukteshwar rainfall station established in 1897 recorded 34.08 cm in 24 hours during October 18-19. The previous record has been 25.45 cm on September 18, 1914. Similarly, the Pant Nagar weather station witnessed 40.39 cm rains. The station was set up in 1962 and previous highest rainfall record was 22.8 cm dated July 10, 1990. This information was revealed and shared on social media by Kavita Upadhyay a Nainital based journalist and researcher.
Referring to data from IMD’s manual observatories and climatology records, Navdeep Dahiya mentioned that Nainital-401 mm, Mukteshwar-341 mm and Pant Nagar-404 mm have recorded highest ever 24 hours rainfall records for all months in recorded history. According to him the previous highest rainfall record for Nainital site was 313.7 mm on September 15, 1957, for Mukteshwar it was 254.5 mm on September 18, 1914 and Pant Nagar 228 mm on July 10, 1990.
Rainfall (mm) at major manual stations on October 18 and 19 as shared by Shubham Misra.
|Manual stations||Oct. 18||Oct. 19|
He further mentioned that in just 4 days between October 16 to 20 (10.0 mm on Oct. 17; 134.0 mm Oct. 18; 535.0 mm Oct, 19 and 30.5 mm Oct. 20.) Nainital AWS at GIC registered 709.5 mm rainfall. [All daily rainfalls are reported for 24 hours ending at 0830 hours in the morning.]
As per daily rainfall report by MC, Dehradun for Oct 18-19 (i.e. 24 hours ending at 0830 hours on Oct 19) at least 24 weather stations received extremely heavy rains while very heavy rains has been reported at 12 sites and heavy rainfall at 1 station.
24 hours Rainfall (≥7 cm) on October 18-19 in Kumaon division.
|AWS/ ARG / MO||Rains (cm)||AWS/ ARG / MO||Rains cm||AWS/ ARG / MO||Rains (cm)||AWS/ ARG / MO||Rains (cm)|
In Garhwal region too, 7 weather stations witnessed very heavy rainfall and 6 other received heavy rainfall during this period.
24 hours Rainfall (≥7 cm) on October 18-19 in Garhwal division.
|AWS/ ARG / MO||Rains (cm)||AWS/ ARG / MO||Rains cm||AWS/ ARG / MO||Rains (cm)|
District wise, Nainital and US Nagar recorded extremely heavy rainfall in 24 hours ending at 0830 hours on Oct 19 and 5 districts Champawat Almora, Bageshwar, Pithoragarh and Chamoli witnessed very heavy rains while 3 districts of Pauri, Rudraprayag and Tehri received heavy rainfall during this period. At state level, against the normal average of 1.1 mm, the 122.4 mm actual rainfall has been registered during October 18-19 which is in very heavy rainfall category.
District wise 24 hours (October 18-19) and cumulative rainfall till October 19, 2021
|24 hours rainfall||18-19 Oct. 2021||Cumulative Rainfall||01-19 Oct. 2021|
|SN||District||Actual (mm)||Normal (mm)||%Dep.||Actual (mm)||Normal (mm)||%Dep.|
Rains on October 19-20, 2021
The rainfall intensity decreased in following 24 hours on October 19-20, 2021 (i.e. 24 hours ending at 0830 hours on Oct 20). As per MC, Dehradun daily rainfall report dated October 20 moderate rains were recorded at 10 stations whereas 8 stations registered heavy rains and 2 sites witnessed very heavy rains in 24 hours spread over 8 districts of state.
|Districts||≥ 5 cm rainfall in 24 hours October 19-20|
|Almora||Almora-7, Takula (AWS)-6, Ranikhet-6, Bhainsiya Chhana (AWS)-5, Matela (AGRO)-5, Dwarahat-5, Almora (AWS)-5|
|Champawat||Lohaghat-12, Devidhura (AWS)-11, Bastia (ARG)-10, Tanakpur (AWS)-5|
|Pithoragarh||Ganai Gangoli (ARG)-13, Pithoragarh-9, Gangolihat (AWS)-8|
|Nainital||Mukteshwar-9, Mukteshwar (AWS)-8|
|US Nagar||Khatima-9, Khatima (AWS)-6|
As for district average only Champawat recorded heavy rainfall.
District wise 24 hours (October 19-20) and cumulative rainfall till October 20, 2021
|24 hours rainfall||19-20 Oct. 2021||Cumulative Rainfall||1-20 Oct. 2021|
|SN||Districts||Actual (mm)||Normal (mm)||% Dep||Actual (mm)||Normal (mm)||% Dep.|
LD* Large Deficit
Rainfall variation in 2nd & 3rd week of October 2021
The weekly rainfall data for October 7-12 and October 14-20 weeks shows sharp contrast between rainfall figures. While all the districts including the state were facing large rainfall deficit in second week of October, the situation totally changed to all the districts and state registering rainfall in large excess.
|Rainfall between||07.13 Oct. 2021||Rainfall between||14-20 Oct. 2021|
|SN||Districts||Actual (mm)||Normal (mm)||%Dept. (mm)||Actual (mm)||Normal (mm)||%Dept. (mm)|
Bhim Singh Rawat (firstname.lastname@example.org)
Note:- Uttarakhand is divided into two major administrative divisions of Garhwal and Kumaon. Out of 13 districts, Garhwal division is comprised of 7 districts namely Uttarkashi, Chamoli, Rudraprayag, Tehri, Pauri, Haridwar and Dehradun, while there are 6 districts under Kumaon division which includes Bageshwar, Pithoragarh, Champawat, Nainital, Almora and US Nagar.
The rains have particularly affected almost all the districts under Kumaun division. The event unfolded after monsoon period when the soil was already saturated and dams, rivers carrying significant water. Following the unusual rain spell there has been several landslides, flash floods causing wide scale destruction.