To understand these sightings, the forecasting team contacted their colleagues at the Lauder Atmospheric Research Station in Central Otago, who confirmed that their ground-based LIDAR (Light Detection and Ranging) instrument has been detecting unusual spikes in aerosols in the stratosphere, at around 20-25 kilometres above New Zealand.

Ten-thousand miles away in England, Simon Proud, a satellite data researcher at the University of Oxford, began to monitor the twitching volcano using an array of satellites.Then, early in the morning on January 14 local Tongan time, a 12-mile-high plume of ash pierced the sky.