Aviation Alert Codes
In New Zealand, we use a system of Aviation Alert Codes to define the current status of each volcano, aimed at pilots who may fly over volcanic areas. The codes range from GREEN to RED.
| ICAO Colour Code | Status of Volcano's Activity |
|---|---|
| GREEN | Volcano is in normal, non-eruptive state. Or, after a change from a higher alert level: Volcanic activity considered to have ceased, and volcano reverted to its normal, non-eruptive state. |
| YELLOW | Volcano is experiencing signs of elevated unrest above known background levels. Or, after a change from higher alert level: Volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase. |
| ORANGE | Volcano is exhibiting heightened unrest with increased likelihood of eruption. Or: Volcanic eruption is underway with no or minor ash emission. |
| RED | Eruption is forecast to be imminent with significant emission of ash into the atmosphere likely. Or: Eruption is underway with significant emission of ash into the atmosphere. |
