By Libby Kirkby-McLeod of RNZ

A steam and gas plume from Whakaari/White Island has been visible from the mainland, but the volcano remains at volcanic alert level 3.

The aviation colour warning for the island remains at “orange” to tell aircraft that a volcanic eruption is under way, but little or no ash is being produced.

GeoNet duty volcanologist Paul Jarvis said a steam and gas plume rose about 3km above sea level, and was visible from the Bay of Plenty coast about 11.30am on Friday.

“Webcam and satellite observations show that the volcanic ash content was minor, and the likelihood of volcanic ash reaching the mainland is very low,” he said.

GeoNet said analysis of webcam images and satellite imagery from MetService suggested the likelihood of significant volcanic ash in the plume was minor.

After about 30 minutes, the plume returned to a more typical altitude of about 1km or less.

“While the plume was highly visible from afar, this does not reflect a significant change of activity at the volcano,” Jarvis said.

“The height that a volcanic plume can reach is determined by a combination of the volcanic activity and atmospheric conditions.”

Bay of Plenty currently has a severe thunderstorm watch, which affects how easily volcanic plumes rise through the atmosphere.

“Given the current atmospheric conditions and the volcanic activity level over recent weeks, it is possible further visibly impressive plumes may be observed,” Jarvis said.

If wind blows the plume towards the Bay of Plenty coast, residents may smell sulphur odours.

“However, at the current level of activity, there is a very low likelihood of ash falling to the ground at the coast,” Jarvis said. “The level of volcanic activity would have to escalate significantly for this likelihood to increase.”

GeoNet monitors the island by remote cameras, satellite imagery and periodic observation, and gas flights.

– RNZ