Major Cloudburst Incidences in the Uttarakhand Himalaya
Past incidences of cloudbursts triggered calamities in the Uttarakhand Himalaya show that the state suffered tremendously. We gathered data on the major cloudburst incidences in Uttarakhand in the monsoon seasons of 2020 and 2021 from the state disaster relief force (SDRF), Dehradun. In three months of April, July, and August 2020, 13 major and numerous minor cloudburst incidences were noticed in Uttarakhand (Table 1). These incidences resulted in the death of 22 people and 77 animals, and 19 houses were fully damaged. Similarly, in the May and July months of 2021, 10 major and 24 minor cloudburst incidences were occurred in the Uttarakhand Himalaya, resulted in the death of 27 people and 94 animals, and 56 houses were buried. Besides, it caused a huge loss to property and landscape degradation.
Table 1
Major cloudbursts occurred in Uttarakhand in 2020 and 2021
Date of occurrence
|
Cloudburst hit area
|
Casualties
|
April-August 2020
|
April 23, 2020
|
Kotdwar (Pauri district)
|
Low-lying areas were flooded and arable land was washed away
|
April 27, 2020
|
Naugaon and Mori (Uttarkashi district)
|
Five houses were partially damaged and agricultural land flown
|
July 14, 2020
|
Dharchula (Pithoragarh)
|
Landslide on the road connecting India-Tibet boarder
|
July 19, 2020
|
Madkot and Tanga (Pithoragarh)
|
Three people were killed and six injured
|
July 20, 2020
|
Bata, Sirtaul, and Munsiyari
|
Eight houses were buried, three people killed, 10 cattle died, and bridges and farmlands washed away
|
July 28, 2020
|
Banagapani (Uttarkashi)
|
47 cattle died
|
July 28, 2020
|
Ghat (Chamoli district)
|
Three houses flown, cowsheds collapsed, and three people died
|
August 9, 2020
|
Gangi village (Tehri)
|
20 cattle were buried
|
August 10, 2020
|
Sirwadi (Rudraprayag)
|
Seven houses were fully damaged
|
August 10, 2020
|
Bageshwar
|
A house was collapsed and a bridge flown
|
August 18, 2020
|
Mori village (Uttarkashi)
|
12 people died
|
August 19, 2020
|
Near Lakhwar Dam (Uttarkashi)
|
A bridge was collapsed
|
August 24, 2020
|
Tali-Ansari (Chamoli)
|
One person died and one injured
|
May-July 2021 (Total 24 incidences)
|
May 3, 2021
|
Kumrada, Baldogi, and Kamad (Uttarkashi)
|
Three people died
|
May 3, 2021
|
Narkota (Rudraprayag)
|
On Three houses damaged and 1-acre arable land was washed away
|
May 3, 2021
|
Khankra, Fatehpur Kotli, Gairsari Narkota
|
One person died
|
May 11, 2021
|
Devprayag town
|
Sixteen buildings were collapsed
|
May 20, 2021
|
Bijnad, Chakrata
|
Three people and 24 animals died
|
May 30, 2021
|
Bangwari village (Pauri)
|
Two cows died and 0.5-acre agricultural land washed away, exiting crops damaged and fruit trees dislocated
|
July 18, 2021*
|
Nirakot
|
One person died, 0.7-acre arable land washed away and three buildings and 5 bridges collapsed.
|
July 18, 2021*
|
Mando
|
Three people and two animals died, 1.2-acre arable land washed away, and five buildings and two bridges collapsed.
|
July 18, 2021*
|
Kankrari
|
One person died, 20.6-acre arable land was washed away, 11 buildings were damaged, and 6 bridges collapsed.
|
July 18, 2021*
|
Siror
|
0.6-acre arable land flown and one bridge collapsed.
|
Source: SDRF (2021) *Present case study villages |
Figure 3 shows economic losses are higher in 2021 than in 2020 due to cloudburst calamities in Uttarakhand. It is because, in 2021, the cloudburst incidences are much more than 2020 even the data of 2021 is only up to July. The figure further shows that animal loss was the highest in both years than houses. It is followed by human loss and then bridges collapsed
Figure 4 shows district wise major cloudburst events that occurred in the Uttarakhand Himalaya in 2020 and 2021. The highest incidences were noticed in Uttarkashi district (total 09), followed by Pithoragarh, Chamoli, and Rudraprayag districts (three incidences each). Pauri and Tehri districts had two incidences and Bageshwar and Dehradun districts had on each.
Case Study of Affected Villages
On July 18 2021, a cloudburst hits the Hari Maharaj Parvat (hilltop) at an altitude of 2350 m at 8:30 pm, which triggered huge debris flows and flash floods. The four villages – Nirakot, Mando, Kankrari (a cluster of three villages including Sada and Thalan), and Siror of Uttarkashi district, located close to Uttarkashi town, were severely affected (Table 2). At the cloudburst hit area, it formed three gullies, which later on merged into three streams, along which these villages are located. The source of debris and flood was one i.e. Hari Maharaj Parvat and it has equally flown in all three directions. Since the cloudburst event occurred at 8:30 pm, the people did not have time to move their household goods, therefore, the damage was enormous. A detailed case study of these villages was conducted and described as follows.
Nirakot
Nirakot is located at an elevation of 1530 m on the upper slope (30º 45' 23'' N and 78º 25' 56'' E) of Mando village and two km downwards from the cloudburst hit area i.e. Hari Maharaj Parvat along the Mando Gadhera (stream). The village is situated on a 30o to 55o slope, surrounded by mixed-oak on the upper slopes and pine on the lower slope. It has a west-facing slope, moderate in the middle and steep in the upper and lower part. The huge debris having 20 cubic m to 2400 cubic m volume and containing boulders, pebbles, gravels, and mud flew, which has devastated settlements, cowsheds, and agricultural lands. Debris shared more than 70%. About 100 mixed oak forests were dislocated by debris flows and about 0.7-acre arable land was destroyed. A total of 22 HHs were affected. Two houses and one cowshed were washed away. About 167 fruits trees were dislocated and about 10 existing crops growing at about 0.7-acre land was destroyed by debris.
Mando
Village Mando is located on the left bank of the Bhagirathi River about 3 km from Uttarkashi town towards Gangotri at the west-facing slope. Situated at an altitude of 1180 m it has 30º44'09'' N and 78º27'16''E coordinates. A stream flows through the village and meets the Bhagirathi River is named Mando Gadhera. The village and its surrounding areas are ecologically fragile and highly vulnerable to geo-hydrological hazards. The distance between the cloudbursts hit the area and the affected area is about 4 km. The large size of boulders, pebbles, and huge debris were flown and deposited in the village, mainly on the bank of the Bhagirathi River. Boulders including debris shared 60-70%. Four km gully erosion occurred with 5x4 m depth and width. The depth and width increase to 6x8 m in its downstream areas. The slope gradient varies from 60o-70o on the upper slope to 30o-55o on the lower slope. Three females and two cows died. About 1.2 acres of arable land completely washed away and similarly, the crops with high biodiversity – paddy, pulses, and green vegetables – were damaged in the given arable land. Five houses, two cowsheds, and 2 bridges washed away. A pipeline was damaged. About 20 fruit trees such as Malta, orange, lemon, and banana were dislocated and flown. About 200 pine and mixed-oak trees were dislocated due to debris flow. This village was also suffered from landslide hazards on 4th July 1984 at 8:00 pm, which has damaged about 0.5 acres of agricultural land and paddy, pulses, and vegetable crops were damaged fully. A house was buried in debris.
Table 2: Salient geographical feature of cloudburst hit areas
Variables
|
Nirakot
|
Mando
|
Kankrari
|
Siror
|
Date of cloudburst
|
18-07-21 (time: 8:30 pm)
|
18-07-21 (time: 8:30 pm)
|
18-07-21 (time: 8:30 pm)
|
18-07-21 (time: 8:30 pm)
|
District
|
Uttarkashi
|
Uttarkashi
|
Uttarkashi
|
Uttarkashi
|
Altitude (m)
|
1530
|
1180
|
1620
|
1280
|
Latitude
|
30º 45' 23''N
|
30º44'09''N
|
30º 38'56''N
|
30º 44'27''N
|
Longitude
|
78º 25' 56''E
|
78º27'16''E
|
78º 27' 56''E
|
78º 29'15''E
|
Slope aspect
|
West-facing
|
West-facing
|
South-facing
|
North-facing
|
Cloudburst hit area
|
Hari Maharaj Parvat (2350m)
|
Hari Maharaj Parvat (2350m)
|
Hari Maharaj Parvat (2350m)
|
Hari Maharaj Parvat (2350m)
|
Distance travel by debris
|
2 km
|
4 km
|
5 km
|
3.5 km
|
Name of stream
|
Mando Gadhera (Tributary of Bhagirathi)
|
Mando Gadhera (Tributary of Bhagirathi)
|
Diya Gadhera (Tributary of Indravati River)
|
Siror Gadhera (Tributary of Bhagirathi)
|
Debris composition and size
|
Large boulders, pebbles, gravels, and mud; boulders’ volume ranging from 65 cubic m to 2300 cubic m (boulder-mud ratio: 55:45)
|
Large boulders, pebbles, gravels, and mud; boulders’ volume ranging from 70 cubic m to 2400 cubic m (boulder-mud ratio: 60:40)
|
Large boulders, pebbles, gravels, and mud; boulders’ volume ranging from 40 cubic m to 2200 cubic m (boulder-mud ratio: 30:70)
|
Large boulders, pebbles, gravels, and mud; boulders’ volume ranging from 30 cubic m to 2200 cubic m (boulder-water ratio: 70:40)
|
Source: A case study
Kankrari
Kankrari is a cluster of three villages – Kankrari, Sada, and Thalan. An average altitude is 1620 m. The coordinates are 30º 38'56''N and 78º 27' 56''E and the slope gradient is 30o-45o. Debris flow travelled 5 km and affected all three villages. Kankrari village is located upstream, heavily damaged, whereas the downstream villages are partially damaged. Diya Gadhera flows through the villages, which is a tributary of the Indravati River, flows into the Bhagirathi River from the left bank before Uttarkashi town. The slope gradient is very high in the upper stream (50o-70o) whereas, in the middle stream, the slope gradient is 30o-45o and lower stream, it is 20o-30o. The depth and width of the gully were 8x7 m in the upper stream, 12x7 m in the middle stream, and 15x5 m in the lower stream with 30% boulders and 70% debris. One person died and six bridges collapsed. About 500 trees were washed away, 20.6 acres of arable land was washed away, 100 HHs affected, 11 houses collapsed about 20.6-acre cropland in which more than 10 crops were grown destroyed, and 300 fruit trees were dislocated. A part of the village is sliding down with houses and agricultural land. The affected people have been shifted to a government school.
Siror
Siror village is located on the left bank of the Bhagirathi River at 1280 m (30º44'27'' N and 78º29'15'' E). The village was partially affected by cloudburst triggered debris flows and flash floods. Siror Gadhera was inundated with debris. The debris travelled about 3.5 km from the cloudburst hit area. The slope gradient varies from 20o to 30o in the lower slope to 60o in the upper slope. The width and depth of debris along the 5 km varied from 4x4 m on the upper slope to 2x2 m on the middle slope and 6x6 m on the lower slope. The debris was contained by 70% boulders and 30% gravels and pebbles. About 0.3-acres of arable land, 70 trees of deodar, and four walnut trees were dislocated. Paddy and pulses fields were washed away, which had 0.3-acre land. A bridge and pipeline were flown with debris.
We have interviewed 143 heads of households, which were affected by cloudburst calamity from all four case study villages. The people of these villages are living in panic. After devastating cloudburst triggered calamity, the people are suffering psychologically. They wanted to rehabilitate in other safe places. Many of them responded that they are unable to sleep at night because of fear of another calamity. The people are living at risk and vulnerability. When the authors asked them about the recent trends of cloudburst incidences, most of them opined that the frequency and intensity of cloudburst calamities are increasing year to year.
Figure 5 shows four villages – Nirakot, Mando, Kankrari, and Siror, which were severely affected by cloudburst triggered debris flows and flash floods. The volume of debris and boulders can be seen in all the villages. These villages are surrounded by dense temperate forests that vary from pine to mixed-oak and deodar. Kharif crops are growing in the arable land whereas a large cropped land has been washed away.
Environmental Impact
The environmental impact of cloudburst triggered debris flow and flash flood in four villages of Uttarkashi district was analyzed (Table 3). The major variables were the number of forest trees dislocated, total land degradation, land degradation under existing crops, number of fruit trees dislocated, land degradation under arable land, number of buildings were damaged, number of bridges damaged, and boulders’ volume. Forest trees, which dislocated were pine in the middle altitude and mixed-oak and deodar in the higher altitude. A total of 770 forest trees were dislocated from all four villages out of which, 500 were from the Kankrari cluster of villages (highest). The lowest trees dislocated were from Siror village (70). Total land degradation from the cloudburst hit area to the affected areas was huge, however, we have measured the land which was within and surrounding each village. The total land degradation was 52.5 acres with the highest in Kankrari (45 acres) and the lowest in Siror (0.5 acres). The land degradation under existing crops was 22.6 acres in all four villages, varies from 0.1 acres in Siror to 20.6 acres in Kankrari. The total number of fruit trees dislocated was 486. Land degradation under arable land was 22.6 acres. It includes the area under existing crops both agriculture and horticulture. A total of 19 buildings were damaged whereas a total of 14 bridges, connecting villages were damaged.
Table 3: Environmental impact of cloudburst triggered debris flow and flash flood
Variables
|
Nirakot
|
Mando
|
Kankrari, a cluster of villages
|
Siror
|
Total
|
Number of forest trees dislocated
|
100
|
100
|
500
|
70
|
770
|
Total land degradation (acre)
|
2
|
4
|
45
|
0.5
|
51.5
|
Land degradation under existing crops (acre)
|
0.7
|
1.2
|
20.6
|
0.1
|
22.6
|
Number of fruit trees dislocated
|
162
|
20
|
300
|
4
|
486
|
Land degradation under arable land (acre)
|
0.7
|
1.2
|
20.6
|
0.1
|
22.6
|
Number of buildings damaged
|
3
|
5
|
11
|
Nil
|
19
|
Number of bridges damaged
|
5
|
2
|
6
|
1
|
14
|
Source: by Authors
Economic Impact
The economic impact of cloudburst triggered debris flow and the flash flood was tremendous in the forms of a household affected, loss of human and animal life, building loss, forest loss, existing crop loss, loss of fruits, loss of arable land, and loss of bridges (Table 4). The value of all these variables was calculated in Indian Rupees (INR) at the current prices. The total number of households affected was 143, of which, 100 households belonged to the Kankrari cluster of villages (highest) and three households (lowest) were from Siror village. Four people died due to the calamity – three women from Mando village and 1 man from Kankrari village. Two cows from Mando village died. The total loss from the collapse of the building was 1.7 million INR, with the highest (1.1 million INR) from Kankrari village. A total of 0.77 million INR was lost due to forest loss, and the loss from existing crops was 3.35 million INR, the second-highest in all other losses. Loss from dislocation of fruit trees was noted high, which was about 0.5 million INR. A large portion of arable land was flown which value was 11.3 million INR, the highest loss. About 14 million INR was lost due to the collapse of bridges. As a whole, about 31.62 million INR was lost due to cloudburst calamity. Per household loss by a cloudburst, calamity was noted 0.22 million INR.
Table 4: Economic impact of cloudburst triggered debris flow and flash flood
Variables
|
Nirakot
|
Mando
|
Kankrari (including Sada and Thalan)
|
Siror
|
Total
|
Number of affected HHs
|
22
|
18
|
100
|
03
|
143
|
Loss of human life
|
Nil
|
3
|
1
|
Nil
|
04
|
Loss of animals (cows)
|
Nil
|
2
|
Nil
|
Nil
|
02
|
Building loss (million INR)
|
0.25
|
0.45
|
1.1
|
Nil
|
1.7
|
Forest loss (million INR)
|
0.1
|
0.1
|
0.5
|
0.07
|
0.77
|
Crops loss (million INR)
|
0.4
|
0.8
|
1.4
|
0.75
|
3.35
|
Loss of fruits (million INR)
|
0.162
|
0.02
|
0.3
|
0.004
|
0.5
|
Loss of arable land (million INR)
|
0.35
|
0.6
|
10.3
|
0.05
|
11.3
|
Loss of Bridges (million INR)
|
5
|
2
|
6
|
1
|
14
|
Total (INR)
|
6.26
|
3.97
|
19.6
|
1.87
|
31.62
|
Source: by authors
Average Circumference, Area, and Volume of Boulders
We calculated the average circumference, area, and volume of boulders in the case study villages used a formula: circumference = 2πR; Area = π * R²; Volume = length x width x depth (Table 5). We noticed that the highest average area of boulders was in Mando village which is 28.3 m2 followed by Kankrari 19.6 m2, Nirakot 12.57 m2, and Siror 7.1 m2. In terms of the total volume of debris, it was the highest in Kankrari, followed by Mando, Nirakot, and Siror.
Table 5: Average circumference, area, and volume of boulders
Variables
|
Nirakot
|
Mando
|
Kankrari (including Sada and Thalan)
|
Siror
|
Radius (m)
|
2
|
3
|
2.5
|
1.5
|
Diameter (m)
|
4
|
6
|
5
|
3
|
Circumference (m)
|
12.57
|
18.8
|
15.7
|
9.4
|
Area (m2)
|
12.57
|
28.3
|
19.6
|
7.1
|
Total volume of debris (cubic m)
|
36000
|
48000
|
62000
|
24000
|
Source: by Author
Figure 6 shows the average diameter of boulders in the cloudburst affected villages. We drew the figure with a scale, 1 cm is equal to 1 m. The average biggest diameter of boulders was found in Mando village (6 m), followed by Kankrari (5 m) and Nirakot (4 m) villages. The average smallest diameter of boulders was found in Siror village (3 m).
Vulnerability Analysis
Based on the above analysis and Table 6, vulnerability analysis of the case study villages was carried out. The main variables of vulnerability were slope gradient, accessibility of villages, economic conditions of households, and climatic conditions. Based on these variables, Nirakot village has a high vulnerability, Kankrari has a high, and Siror and Mando have a moderate vulnerability.
Table 6: Vulnerability analysis of case study villages
Variables
|
Nirakot
|
Mando
|
Kankrari (including Sada and Thalan)
|
Siror
|
Slope gradient
|
30º-55º
|
30º-55º
|
30º-45º
|
20º-30º
|
Accessibility
|
Highly inaccessible
|
Accessible
|
Inaccessible
|
Accessible
|
Economic condition
|
Not favourable
|
Average
|
Not favourable
|
Average
|
Climate
|
Cold in winter
|
Conducive
|
Cold in winter
|
Conducive
|
Vulnerability
|
Very high
|
Moderate
|
High
|
Moderate
|
Source: by Authors