Extreme Rainfall Alert: Navigating Nature’s Wrath with Preparedness

As global weather patterns grow increasingly volatile, extreme rainfall has emerged as one of the most unpredictable and destructive threats—triggering flash floods, landslides, urban inundation, and infrastructure chaos. Today’s blog dives deep into what constitutes an extreme rainfall alert, how such warnings work in India, why they're more frequent, how to interpret them, and how individuals and communities can prepare effectively.

Understanding Extreme Rainfall Alerts

What Defines an Extreme Rainfall Alert?

An extreme rainfall alert signifies imminent or ongoing rainfall surpassing normal intensity—typically heavy enough to cause flood risk, landsliding, and transport and infrastructure disruptions. India Meteorological Department (IMD) employs a color-coded warning system to communicate severity:

• Yellow (Be Aware): Significant rainfall possible.

• Orange (Prepare for Impact): 115.6–204.4 mm expected in 24 hours; elevated risk of flooding.

• Red (Take Action): Over 204.5 mm expected; serious threat to life and property—evacuations may be needed.
  

Causes Behind Extreme Rainfall

Multiple factors contribute to extreme rainfall alerts:

• Active weather systems: monsoons, cyclones, depressions, or low-pressure zones serve as triggers.

• Topography: Mountain slopes and valleys intensify rain in localized areas.

• Atmospheric instability: Warm, moist air collides with cooler air, enabling rapid convective cell formation.

• Climate change and urbanization: Increased atmospheric moisture and blocked runoff due to built environments exacerbate risks.
  

Real-World Context & Frequency

Recent Alerts and Regions in Focus

In June 2025, IMD issued severe rainfall alerts across major Indian regions—Maharashtra (Mumbai, Pune), Telangana, Andhra Pradesh, Odisha, Chhattisgarh, Northeast India, Karnataka, and Kerala’s coastal belts—prompting widespread preparedness measures. NDRF deployments, dam monitoring, and evacuation advisories heightened readiness.

Cloudbursts: Dangerous Sudden Downpours

A striking example is the deadly cloudbursts in the Himalayas—defined as over 100 mm in just one hour, often above 150 mm. In 2025 alone, these events in Uttarakhand and parts of Pakistan resulted in hundreds of deaths, fueled by sudden floods and landslides. Such events are nearly impossible to forecast days in advance.

Interpreting Alerts and Taking Action

Color-Coded Alerts: What They Mean

IMD’s color warning system helps translate forecast risk into public action:

Safety Tips During Alerts

Residents should:

• Avoid waterlogged roads or low-lying areas.

• Secure outdoor items and clear drainage.

• Keep emergency kits ready—flashlight, first aid, power backup.

• Avoid electric poles, unstable structures.
  

During commutes:

• Avoid flooding-prone routes and underpasses.

• Use reliable navigation tools.

• Drive slowly with caution; two-wheeler travel is riskier.
  

Community-level actions:

• Rely on official IMD updates via apps or social media.

• Do not spread misinformation.

• Participate in evacuation drills in flood-prone areas.
  

Enhancing Forecasts and Response Systems

Improved Forecast Accuracy

IMD’s accuracy has dramatically improved, with Probability of Detection (PoD), Critical Success Index (CSI), and Heidke Skill Score (HSS) rising over 40% in day‑1 alerts and even higher for day‑3 forecasts between 2017–2018 compared to earlier years. Enhanced models, better data assimilation, and consensus forecasting methods were key contributors.

Next-Gen Tech: AI, Radar & Early Warnings

Forecasting has transformed with:

• Radar systems, especially in sensitive regions like the Himalayas, to detect rapid developments.

• Telecom mapping, satellites, radar, AI enhancing temporal and spatial resolution in warnings.

• Community apps like AI-based hyperlocal systems (e.g., mausam.aimindia.in) that generate precise alerts tailored to each neighborhood.
  

Lessons from History & Current Scenarios

Past Tragedies and Policy Learning

• 2020 Kerala floods: Over ₹19,000 crore in damage and 100+ fatalities. Lessons included delaying dam releases and uncoordinated warning systems. Government later invested in evacuation camps and multipurpose shelters.
  

• Early Warning Protocols: Kerala's EWS categorizes alerts into levels—with clear actions linked to yellow, orange, and red zones.
  

• IMD’s Kerala alerts (2023): Orange then red alerts were issued progressively ahead of severe rains. Nowcasts via SMS helped officials act.
  

Recent Alerts and Response Frameworks

States facing severe alerts in mid-2025 deployed NDRF teams, alerted coastal fishermen, and operationalized district disaster control rooms and community-level plans. Social media and apps played vital roles in disseminating advisories.

Quick Reference: What You Need to Know

• Definition: Extreme rainfall alerts warn of imminent heavy rainfall—yellow, orange, or red based on intensity.

• Trigger factors: Monsoon systems, topography, climate change, urbanization.

• Impact forecast:

  • Yellow: Possible disruptions.

  • Orange: Stock supplies; expect floods.

  • Red: Take emergency action; possible evacuation.

• Safety essentials:

  • Avoid travel, charge devices, prepare kits.

  • Secure property; heed official messaging.

• Technology role:

  • Improved radar and AI-based forecasting yield better accuracy.

  • Community-level alert systems help disseminate updates.

• History & learning:

  • Past mega-floods show need for timely evacuation, infrastructure resilience, and coordinated messaging.

• What to do:

  • Stay alert both personally and as a community member.

  • Follow IMD warnings and local advisories.

  • Plan evacuations if needed; help vulnerable neighbors.

Conclusion

An Extreme Rainfall Alert is more than just a headline—it’s a call for action. Understanding the alert levels and responding wisely can be the difference between safety and crisis. While weather forecasting has improved, its efficacy depends on quick public comprehension, community-level preparedness, and infrastructure resilience.

As climate change intensifies, such warnings are becoming frequent. Staying informed, enabling robust early warning systems, and advancing collective readiness are vital steps. Resilient communities don't just survive extreme rainfall—they adapt and emerge stronger.