South-West Monsoon
• The Southwest Monsoon is a seasonal wind system that brings over 70% of India’s annual rainfall during June–September.
• It plays a critical role in agriculture, water availability, and overall economic activity.
What is Onset of Monsoon?
• The onset of the monsoon (June-September) when the monsoon winds reaches over the Indian subcontinent.
• This shows the arrival of southwest monsoon at Kerala.
• The India Meteorological Department (IMD) declared the onset of the southwest monsoon eight days ahead.
Factors Affecting Early Onset of South-West Monsoon
• Madden-Julian Oscillation (MJO) eastward-moving disturbance in the tropics helped boost rainfall and wind patterns favorable for monsoon advancement. When it is in favorable phase it can enhance rainfall over India during the monsoon season.
• Mascarene High as a high-pressure area found around the Mascarene Islands (in the south Indian Ocean) aided in directing moist winds to Indian coastlines.
• Somali Jet a cross-equatorial wind when it is strong accelerates the monsoon’s progress.
• Vertical movement of heat and moisture in the atmosphere when strong leads to rainfall known as convection.
• Intense pre-monsoon heating created a strong low-pressure over Pakistan and NW India zone that pulled in moist winds more quickly than usual.
• A positive IOD phase (warmer western Indian Ocean) may have contributed to stronger monsoon currents.
• Monsoon Trough low-pressure zone stretching from Arabian Sea to Bay of Bengal activated rainfall over central India and NE India.
Impact of Early Monsoon
• Early monsoon facilitates timely sowing of major Kharif crops ensuring higher productivity.
• Early rainfall recharges groundwater, fills reservoirs, and improves irrigation, essential for both agriculture and hydropower generation.
• Early rains helped replenish drought-prone regions like Tamil Nadu and Karnataka.
• Early onset may or may not ensure a longer or stronger monsoon season, posing risks of localized flooding and damage to standing crops.
Threats of Urban Flooding
• Urban flooding has become a growing concern in Indian cities due to rapid urbanization, outdated infrastructure, and climate change.
• In response, both national and local authorities are stepping up with a mix of policy reforms, infrastructure upgrades, and community initiatives.
Solutions
• Upgrading Drainage Systems: Cities must modernize stormwater drains to handle heavy rainfall efficiently.
• Rainwater Harvesting: Encouraging rooftop rainwater collection reduces surface runoff and replenishes groundwater.
• Permeable Roads and Pavements: Using porous materials allows water absorption, minimizing flooding.
• Restoring Natural Water Bodies: Reviving lakes and wetlands improves urban flood resilience.
• Improved Waste Management: Preventing plastic waste from clogging drainage systems enhances water flow.
• Climate-Resilient Urban Planning: Integrating flood-resistant designs into city infrastructure.
• Early Warning Systems: Real-time alerts help residents prepare for extreme rainfall events.