"Odisha Faces Record Monsoon Rainfall and Flood Risk"
Monsoon depression
a low-pressure weather system over the Bay of Bengal that brings widespread multi-day rainfall inland.
Indian Ocean Dipole (IOD)
a sea-surface temperature difference between the western and eastern Indian Ocean affecting monsoon rainfall.
Much of the east coast's monsoon rainfall comes from low-pressure systems that form over the warm waters of the Bay of Bengal. The India Meteorological Department (IMD) classifies these systems in rising order of intensity: Low Pressure Area, Depression, Deep Depression, and Cyclonic Storm, based on associated wind speed. Odisha's current season has been shaped by an unusually large number of such systems, including 11 separate ones over the Bay of Bengal, rather than by one dominant cyclone.
The IMD had initially forecast a near-normal monsoon (90% of the long-period average), partly because an El Nino was expected to develop, and El Nino conditions typically weaken the moisture flow that feeds the south-west monsoon. Instead, Odisha ended June with a large rainfall deficit and then saw a sharp reversal. This is consistent with a well-established pattern in Indian monsoon science: a positive Indian Ocean Dipole (IOD), a difference in sea-surface temperature between the western and eastern Indian Ocean, can offset El Nino's suppressing effect on Indian rainfall. This is why El Nino status alone cannot reliably predict how a season will actually unfold.
Geography compounds this variability. Odisha's south is largely highland, with slopes vulnerable to landslides, while its coast is a low-lying depositional plain built by multiple river deltas, including those of the Mahanadi, the Brahmani-Baitarani system and the Subarnarekha. Rivers such as Nagavali and Vamsadhara rise in the Eastern Ghats, while Brahmani and Subarnarekha originate on the Chotanagpur Plateau; all eventually cross the same low-gradient coastal plain, through which water drains slowly into the sea. After the deadly 1999 Super Cyclone, the state set up the Odisha State Disaster Management Authority (OSDMA) and built a 'zero casualty' evacuation-centred model, later validated in cyclones such as Phailin and Fani.
A monsoon depression forms when moist air converges over warm sea surface, intensifies through latent-heat release, and then tracks northwest across the Odisha-Chhattisgarh belt, dropping heavy rain along its path. A season with 11 such systems means repeated rainfall pulses rather than a single peak event, each pulse arriving before soil, reservoirs and drains have recovered from the last. Once soil is saturated and local storage is full, additional rain converts almost immediately into surface runoff rather than being absorbed, a threshold effect that engineering design must anticipate.
This synoptic-scale, multi-day rainfall differs mechanically from a cloudburst, an extremely intense, highly localized downpour, usually over hilly terrain, produced by rapid orographic lifting of moist unstable air within a narrow valley. …
Consider the following rivers:
1.Brahmani
2.Nagavali
3.Subarnarekha
4.Vamsadhara
Which of the above rise from the Eastern Ghats?
With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct?
1.IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.
2.An IOD phenomenon can influence an El Nino's impact on the monsoon.
Select the correct answer using the code given below:
Comment on the resource potentials of the long coastline of India and highlight the status of natural hazard preparedness in these areas.
Explain the mechanism and occurrence of cloudburst in the context of the Indian subcontinent. Discuss two recent examples.
With reference to the classification of low-pressure weather systems by the India Meteorological Department (IMD), match List-I with List-II and select the correct answer:
List-I (System)
A.Low Pressure Area
B.Depression
C.Deep Depression
D.Cyclonic Storm
List-II (Approximate associated wind speed)
1.Less than 31 km/h
2.31-49 km/h
3.50-61 km/h
4.62-88 km/h
Consider the following statements regarding factors influencing India's south-west monsoon rainfall:
1.El Nino conditions are generally associated with weaker south-west monsoon rainfall over India.
2.A positive Indian Ocean Dipole (IOD) can offset the suppressing effect of an El Nino on Indian monsoon rainfall.
Which of the statements given above is/are correct?
Consider the following statements about disaster management in Odisha:
1.The Odisha State Disaster Management Authority (OSDMA) was constituted following the 1999 Odisha Super Cyclone.
2.Odisha has since pursued a 'zero casualty' approach to cyclone and flood disaster management.
Which of the statements given above is/are correct?
A long-term study (1901-2020) of Odisha's rainfall patterns reported which of the following?
1.The frequency of heavy-rain days has been declining over the period.
2.Maximum one-day and five-day rainfall bursts have been becoming more frequent.
Which of the statements given above is/are correct?
Which of the following best explains why Odisha's coastal plain is prone to prolonged waterlogging during intense rain events?
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