Cyclone Montha, classified as a Severe Cyclonic Storm (SCS), made landfall in Andhra Pradesh, bringing heavy rainfall, strong winds, and widespread damage across coastal Andhra Pradesh, Odisha, and parts of Tamil Nadu.
- Formed over the west-central Bay of Bengal (BoB) as a low-pressure system before intensifying into a cyclone.
- Wind Speed Range: 89–117 kmph.
Cyclone Montha- Key Details
- Formation: Originated as a low-pressure area over the west-central Bay of Bengal.
- Development: Rapidly intensified into a Severe Cyclonic Storm due to favourable oceanic and atmospheric conditions.
- Movement: Driven westward by easterly trade winds (between 5°–20° latitudes) — a typical pattern that pushes cyclones toward India’s east coast.
- Landfall: Along the Andhra Pradesh coast; heavy rain and wind caused infrastructural and agricultural damage across Andhra Pradesh, Odisha, and northern Tamil Nadu.
Significance of Cyclone Montha
- Reinforces Bay of Bengal’s cyclone vulnerability.
- Highlights importance of early warning systems and preparedness under NDMA and IMD.
- Tests coastal resilience initiatives like ODRAF (Odisha Disaster Rapid Action Force) and AP Disaster Response Teams.
- Strengthens focus on climate adaptation, coastal zoning, and mangrove conservation.
Cyclone Naming
- Name: Montha – a Thai word meaning beautiful or fragrant flower.
- Proposed by: Thailand.
- Naming Authority: WMO/ESCAP Panel on Tropical Cyclones (PTC) — responsible for naming cyclones in the North Indian Ocean region (Bay of Bengal & Arabian Sea).
- Cyclone names are:
- Gender-neutral, culturally neutral, maximum eight letters.
- Chosen to ensure clarity, global acceptance, and effective disaster communication.
- Naming Criteria: When wind speeds reach ≥62 km/h, the cyclone is assigned a name.
What is a Cyclone?
- A cyclone is a large-scale air mass that rotates around a low-pressure centre, bringing high winds, thunderstorms, and heavy rain.
- Cyclones are tropical storms, forming between Tropics of Cancer and Capricorn, where warm waters provide the energy needed.
Rotation:
- Anticlockwise in the Northern Hemisphere.
- Clockwise in the Southern Hemisphere.
Known regionally as:
- Hurricane– Atlantic & Eastern Pacific.
- Typhoon– Western Pacific.
- Cyclone– Indian Ocean & South Pacific.
Mechanism of Cyclone Formation
As per NDMA and NOAA, the process involves:
Warm Ocean Water (≥27°C):
- Acts as the main energy source.
- Extends up to 60–70 metres depth.
- Fuels rapid evaporation and convection, releasing latent heat that powers the cyclone.
Coriolis Force:
- Induced by Earth’s rotation- causes air to spin around low-pressure zones.
- Absent near the Equator (cyclones rarely form within 5° latitude).
- About 65% of cyclones form between 10°–20° latitudes.
Pre-existing Low-Pressure Area:
- Provides the initial trigger; moist air rises, intensifies pressure gradient.
High Humidity (Mid-Troposphere):
- Ensures sustained cloud formation and latent heat release.
Weak Vertical Wind Shear (<10 m/s):
- Allows cyclone’s vertical development without disruption.
Upper-Level Divergence:
- Outflow of air aloft maintains low surface pressure and continuous inflow of moist air.
Why Bay of Bengal Experiences More Cyclones
Funnel-like Shape:
- Concentrates storm surges and amplifies impact near coastal regions.
High Sea Surface Temperature:
- Bay waters are warmer than the Arabian Sea → ideal for cyclone intensification.
Topography:
- Complex coastal geometry with deltas, estuaries, and pocket bays influences storm surge behavior.
Climatic Factors:
- Ocean disturbances (low pressure or depressions) commonly form in October, moving westward from the South China Sea.
Climate Change:
- Rising sea temperatures are increasing the intensity and frequency of cyclones along both the east and west coasts of India.
Normal October Activity (IMD data):
- 1 cyclone + 2 cyclonic disturbances = normal monthly pattern.
- Peak Season: October–November (transition period).
WMO–ESCAP–PTC
Formation and Function:
- Full form: World Meteorological Organization / United Nations Economic and Social Commission for Asia and the Pacific – Panel on Tropical Cyclones.
- Established: 1972
- Purpose: Coordinates cyclone warning, forecasting, and naming in the North Indian Ocean region.
- Member countries (13): Bangladesh, India, Iran, Maldives, Myanmar, Oman, Pakistan, Qatar, Saudi Arabia, Sri Lanka, Thailand, UAE, and Yemen.
- Coordinating Agency: WMO Tropical Cyclone Programme, along with Regional Specialized Meteorological Centres (RSMCs) and Tropical Cyclone Warning Centres (TCWCs).
- India Meteorological Department (IMD) – One of six RSMCs globally; responsible for cyclone forecasting and naming for the Bay of Bengal and Arabian Sea.
Expansion:
- In 2018, the panel expanded from 8 to 13 members.
- Each country contributes 13 cyclone names, forming a list of 169 names (released in April 2020 by IMD).
Benefits of Naming:
- Enhances public awareness and scientific communication.
- Simplifies warning dissemination, disaster preparedness, and media reporting.
- Ensures neutrality — no political, religious, or cultural references.
Key Facts
| Topic | Key Facts |
| Cyclone Classification (IMD) | Depression (31–49 kmph), Deep Depression (50–61 kmph), Cyclonic Storm (62–88 kmph), Severe Cyclonic Storm (89–117 kmph), Very Severe (118–165 kmph), Extremely Severe (166–221 kmph), Super Cyclone (≥222 kmph). |
| Cyclone Tracking Agency in India | India Meteorological Department (IMD) – headquartered in New Delhi under Ministry of Earth Sciences. |
| Recent Notable Cyclones in India | Cyclone Mocha (2023), Cyclone Michaung (2023), Cyclone Tauktae (2021), Cyclone Amphan (2020), Cyclone Fani (2019). |
| Difference between Tropical & Extratropical Cyclones | Tropical: Warm core, develops over oceans, derives energy from latent heat. Extratropical: Cold core, forms outside tropics, draws energy from interaction of air masses. |
| Global Cyclone Equivalents | Hurricane – Atlantic/Eastern Pacific; Typhoon – Western Pacific; Cyclone – Indian Ocean/South Pacific. |
| Cyclone Season in India | Pre-monsoon: April–June; Post-monsoon: October–December (most active). |
| Recent WMO Head | Celeste Saulo (Argentina) – first woman Secretary-General of WMO (from Jan 2024). |