El Nino Watch

GDACS alerts (green, orange, red)

A UN / European Commission system that rates each new disaster by its likely humanitarian impact: green (low), orange (medium), red (high, international help likely needed).

Hazards

GDACS (Global Disaster Alert and Coordination System) is run by the European Commission's Joint Research Centre with the UN. It automatically detects cyclones, floods, droughts, earthquakes, volcanoes and wildfires, and estimates their impact.

The colour is about impact on people, not only about the strength of the hazard. It combines hazard severity, how many people are exposed, and how vulnerable the country is. For tropical cyclones, for example:

  • Green: for example a tropical storm affecting fewer than 10 million people, or storm surge up to 1 m.
  • Orange: for example a Category 1-2 cyclone affecting 100,000+ people in medium-to-high vulnerability areas, or surge of 1-3 m.
  • Red: for example a Category 3 cyclone affecting 100,000+ people in medium-to-high vulnerability areas, or surge of 3 m or more.

A strong storm over an empty ocean can be green. The alert is automatic and can change as the storm moves.

How to read it

Coloured symbols on the Map. Click one for the GDACS report link. Distance to Samui matters as much as the colour.

Why it matters for Koh Samui

The cyclone part of the Samui risk level uses GDACS: an orange or red tropical cyclone within 300 km of Samui is the only single hazard that sets the level to 4 Leave (rule R4a).

Sources

Related

ENSO status now

ONI (NOAA CPC)
+1.80 °C, JJA 2026 (previous +1.39 °C)
RONI (NOAA CPC)
+1.36 °C, JJA 2026
Nino 3.4 weekly (NOAA CPC / OISST)
+3.0 °C anomaly, week of 16 Sep 2026 (SST 29.6 °C)