Thunderstorms: Causes, Impacts and Policy Response

Syllabus: GS1/Geography; GS3/Environment

Context

• More than 100 people lost their lives due to severe thunderstorms and dust storms that struck Uttar Pradesh during the pre-monsoon season.

What are Thunderstorms?

• A thunderstorm is a weather phenomenon associated with lightning, thunder, strong winds, heavy rainfall and sometimes hailstorms.
• These events are common during April and May and are observed in many arid and semi-arid regions of the world.
• Key features include sudden development, strong gusty winds, lightning and thunder, short duration but high intensity, and associated dust storms in dry regions.
• Thunderstorms form due to atmospheric instability caused by differences in temperature and moisture between the lower and upper atmosphere.

Conditions Responsible for Formation

• Intense Surface Heating: Northern India experiences extremely high temperatures, often above 45°C during summer. This heats the land surface rapidly.
• Availability of Moisture: Moisture-laden winds from the Bay of Bengal move towards northern India through southeasterly winds.
• Cool and Dry Upper Air: Western Disturbances bring cooler air in the upper atmosphere. When warm moist air rises and meets cooler dry air above, instability develops.
• Convection Process: The warm air rises rapidly, condenses into cumulonimbus clouds and releases latent heat, strengthening vertical air movement and producing thunderstorms.

Types of Thunderstorms

• Single-Cell Thunderstorms: Small and short-lived; usually less destructive; and common in summer afternoons.
• Multi-Cell Thunderstorms: Multiple storm cells clustered together; longer duration; and produce strong winds and heavy rainfall.
• Squall Lines: Organized lines of thunderstorms; common in northern India during pre-monsoon months; and associated with severe wind damage.
• Supercell Thunderstorms: Highly organized rotating storms; rare in India; and can produce extreme winds and hail.
  • The recent Uttar Pradesh storms resembled organized multi-cell thunderstorms with severe squall-line characteristics.

Impacts of Severe Thunderstorms

• Loss of Human Life: The recent storms caused over 100 deaths, mainly due to falling trees, wall collapses, lightning strikes, and flying debris.
• Damage to Infrastructure: High-speed winds uprooted trees and damaged electricity poles, transmission lines, houses and weak structures, hoardings and billboards.
• Agricultural Losses: Thunderstorms and hailstorms damage standing crops, affecting wheat, vegetables, and mango orchards. It impacts farmer incomes and rural livelihoods.
• Disruption of Public Services: Power outages, communication disruption, and transport interruptions.
• Increased Disaster Vulnerability: Rapid urbanization, weak housing structures and inadequate awareness increase vulnerability to such localized disasters.
• Challenges in Forecasting: Evacuation is difficult because thunderstorms are dispersed and unpredictable in movement, unlike cyclones.
  • Localized Nature: Thunderstorms are highly localized and evolve rapidly.
  • Rapid Intensification: Wind speeds can intensify within minutes.
  • Multiple Storm Cells: Several storms can occur simultaneously across different districts.

Government Measures and Policy Support

• IMD’s Early Warning Systems: IMD regularly issues weather bulletins, thunderstorm alerts, and nowcasts (short-term forecasts). IMD has strengthened its observation infrastructure in Uttar Pradesh with nearly 2,400 weather stations for real-time monitoring.
  • Key initiatives include Doppler Weather Radars, mobile weather alerts, and nowcast services.
• National Disaster Management Authority (NDMA): NDMA has issued guidelines for lightning safety, thunderstorm preparedness, and public awareness campaigns.
  • Sachet Portal (National Disaster Alerts): NDMA has envisioned a Common Alerting Protocol (CAP) based Integrated Alert System on Pan India basis. It involves near real-time dissemination of early warning through multiple means of technology using geo-intelligence.
  • Suggested measures are to avoid open fields during lightning, stay indoors during storms, secure loose objects and structures, and strengthen local disaster response systems.
• Lightning Resilient India Campaign: A multi-stakeholder initiative aimed at reducing lightning deaths, community awareness, and scientific forecasting.
• State Disaster Response Measures: State governments undertake compensation for victims, emergency restoration of power supply, relief and rehabilitation assistance.

Way Forward

• Improve Forecast Accuracy: Better high-resolution weather models, expansion of radar networks, and AI-based forecasting systems.
• Strengthen Public Awareness: Community-level preparedness can reduce casualties significantly.
• Climate-Resilient Infrastructure: Stronger housing structures, underground power lines where feasible, and disaster-resilient urban planning.
• Integration with Disaster Management: Thunderstorms should receive greater attention under local disaster management plans similar to floods and cyclones.

Source: IE