Water spout captivates locals in Hawke Bay near Napier

by Astrid Austin
Wednesday, Apr 14, 2021 8:30 PM

A well developed and unusual water spout, merely a few kilometres off the coast of Napier, has captivated the attention of people far and wide.

NIWA principal scientist Chris Brandolino said the water spout - a water funnel resembling a tornado - was caused by the right conditions coming together at the right time.

"In very simple terms, basically you need a thunderstorm and then generally, for at least the kind of water spouts that happened today, you want air changing direction with height."

Called 'Wind Shear', this difference in wind speed or direction over a relatively short distance in the atmosphere produces spin, that when combined with thunderstorms, "can lead you down the path of the waterspout or tornado".

"And in the atmosphere we had a weather system moving through in the upper levels. We had what we call vorticity and that basically is energy in the upper portion of the atmosphere that can increase spin and increase lift and those things can help generate tornados."

However, Mr Brandolino says that this does not necessarily mean a waterspout will be produced.

"You need not only the conditions to exist but they need to kind of come together at the right time and that's what happened to eventualise or materialise into what we saw today but they do happen."

Mr Brandolino says while it is unusual, it is not unheard of in New Zealand. "Tornados and water spouts are more common in other areas of Aotearoa such as the Taranaki region, the Auckland region and North Shore, and the West Coast of the South Island.

"That Hawke's Bay area, offshore, doesn't get a lot of tornados or water spouts so in that case, it is a bit unusual.

After today, things will really settle down for at least the next 24 to 36 hours, he says.

"Things are settling down now as we speak and tomorrow will be a much quieter day, in fact just a couple odd showers if that."

However, the region can expect some more showers, possibly heavy, by Saturday.

Metservice forecaster Tuporo Marsters said it started forming about 5pm, near Clive where the river mouth is.

"As it moved closer to the city it started to get more energy, and then around about 5.30pm the water spout developed, and we got a few lightning strikes out of it. Mr Tuporo said.

By 6pm, the cell had moved away, out to sea. "Most of the upward motion has moved away with it, out to sea."