Volcano Eruptions

Flights were disrupted and airlines placed on alert after an undersea volcano erupted off the coast of Tonga and shot clouds of smoke, steam and ash thousands of metres into the sky.

Both Airways New Zealand which manages air traffic and MetService have issued a warning to aircraft flying in the area. New Zealand flights were forced to fly around or over the ash and smoke, which reached up to 15,000 metres, an Airways NZ spokeswoman said.

Volcanic ash cannot be detected by planes' weather radar but can cause multiple engine failure. In 1990, a KLM Boeing 747 lost all four engines while flying through a volcanic ash cloud in Alaska.

The Tongan volcano, which is believed to have erupted on Monday, spewed columns of ash from the sea about 10km from the southwest coast off the main island of Tongatapu, where up to 36 undersea volcanoes are clustered, said Tonga's geological service head, Keleti Mafi.

"It's a very significant eruption, on quite a large scale."

Trade winds were blowing gas and steam away from the island so there was no danger to residents.

# posted by kevin : 9:49 PM