Chapter 3 · Topic 3.2 · Prelims + Mains2 of 2
Community & Technology in DM: Early warning and mapping
Key points
- Four parts of early warning: know the risk, monitor and forecast, spread the warning, people able to act.
- SACHET (NDMA, built by C-DOT) sends location-based SMS alerts using the Common Alerting Protocol; INCOIS warns of tsunamis.
- Hazard zonation colours land from very high to low risk; GSI has mapped about 4.3 lakh sq km at 1:50,000.
Prelims box: facts and traps
| Agency or system | Warns about |
|---|---|
| IMD | Cyclones, heavy rain, heatwaves, lightning |
| Central Water Commission | River floods |
| INCOIS, Hyderabad | Tsunamis, storm surges, high waves |
| Geological Survey of India | Landslide forecasts |
| SACHET (NDMA, C-DOT) | Location-based SMS alerts (CAP) |
| Damini app | Lightning |
- Trap: river flood forecasts come from the Central Water Commission, not IMD.
- Mission Mausam (2024) aims for a ‘weather-ready and climate-smart’ India.
Early warning systems
It has four parts: knowing the risk, monitoring and forecasting, spreading the warning, and the public’s ability to act on it. Like a smoke alarm, it’s useless if nobody knows the exit. India’s cyclone death toll fell because all four improved together. The UN’s Early Warnings for All plan (2022) wants every person on Earth covered by 2027.
| Agency or system | Warns about |
|---|---|
| IMD (Doppler radars, INSAT-3D/3DR satellites, impact-based forecasts) | Cyclones, heavy rain, heatwaves, lightning |
| Central Water Commission | River floods |
| INCOIS, Hyderabad | Tsunamis, storm surges, high waves |
| Geological Survey of India | Regional landslide forecasts |
| NDMA’s Integrated Alert System (SACHET), built by C-DOT | Location-based SMS alerts using the Common Alerting Protocol |
| Mobile apps: Mausam, Meghdoot, Damini | Weather, farm advisories, lightning |
“Impact-based” means saying what the weather will do (“roofs may fly off”), not just what it is (“winds of 150 km/h”).
Mission Mausam (2024) aims to make India ‘weather-ready and climate-smart’ with more radars and better models. ISRO’s National Database for Emergency Management gives responders maps and satellite data.
What UPSC asks: four parts, SACHET uses CAP.
Hazard zonation mapping
Mains 2019 stated: Disaster preparedness is the first step in any disaster management process. It asked how hazard zonation mapping will help disaster mitigation in the case of landslides. Zonation divides land into very high to low hazard zones, using slope, geology, rainfall, land use and past slides. It helps by:
- keeping houses, schools and hospitals out of very high zones,
- guiding safe road alignment and slope protection,
- placing rain gauges and warning sensors where they matter,
- planning evacuation routes.
The Geological Survey of India has mapped landslide susceptibility for about 4.3 lakh sq km at 1:50,000.
Disaster preparedness is the first step in any disaster management process. Explain how hazard zonation mapping will help disaster mitigation in the case of landslides.
The same idea works for flood plains, city quake maps, cyclone and heatwave maps.
What UPSC asks: GSI 1:50,000 maps.
Mains box: analysis and answer points
- Hazard zonation for landslides (Mains 2019, 15 marks): what goes into the map, then four uses (siting, roads, sensors, evacuation), with the GSI 1:50,000 mapping as proof.
- Value addition: impact-based forecasting and the UN Early Warnings for All target of 2027.
- Next likely angle: last-mile alerts and why warnings fail.
Practice
Write an answer
In 150 words, explain the significance of Community & Technology in DM with one recent example.
Flashcards (13)
Four parts of early warning?
Risk knowledge, monitoring, dissemination, response.
River flood forecasts?
Central Water Commission.
Tsunami warnings?
INCOIS, Hyderabad.
SACHET built by?
C-DOT, for NDMA.
Alert standard used?
Common Alerting Protocol.
Lightning app?
Damini.
Farm weather app?
Meghdoot.
Mission Mausam year?
2024.
NDEM run by?
ISRO.
Hazard zonation uses?
Slope, geology, rain, land use, past slides.
GSI landslide map scale?
1:50,000.
Area mapped by GSI?
About 4.3 lakh sq km.
Seismic microzonation?
City-level quake hazard maps.
In the news
- 17 Oct 2026Chorbagan pandal stampede in Kolkata kills 19: what went wrong and how crowds should be managed
- 17 Oct 2026IITM Pune holds first consultation of the Climate Science into Services for India Forum
- 13 Oct 2026IMD launches a map-based Decision Support System for cyclone and marine warnings
- 26 Aug 2026India offers flood relief to Nepal; PM speaks to Nepal PM
Disaster Management →All Disaster Management topics