New Zealand is experiencing an increase in the number of tornadoes, according to a NIWA scientist.
In the latest issue of NIWA's flagship publication Water & Atmosphere, Dr Richard Turner explains that the number of tornadoes in New Zealand is higher than it has been for the past 40 years.
Dr Turner also outlines a new research tool being developed by NIWA and GNS Science that will estimate the impact of damage and loss on New Zealand buildings for various natural hazards.
Up until now international formulae have been applied to estimate damages but New Zealand buildings use different construction materials and methods which alters the amount of damage likely to be caused.
New Zealand tornadoes generally last for a couple of minutes, travelling two to five kilometres during that time at speeds between 115 and 180kph.
Warning signs can include hail or heavy rain, followed by calm or a fast, intense wind shift and large, dark, low-lying clouds.
Also in the latest issue of Water & Atmosphere, NIWA reveals the results of a survey in the Cook Strait immediately following the 6.5 magnitude July earthquake.
NIWA's research vessel Tangaroa was diverted to survey the seafloor to determine whether there had been any changes due to near-surface faulting in the Cook Strait Canyon.
The Cook Strait Canyon is the most prominent undersea feature of Cook Strait – scarred by numerous large submarine landslides and active faults.
The survey supported research that the level of ground shaking was not sufficient to trigger submarine landslides which pose a tsunami hazard in this area.
NIWA ocean geologist Dr Joshu Mountjoy said the earthquake occurred near on the least stable regions of the canyon.
"Despite the significance of the event in Marlborough and Wellington, it was well below the level of ground shaking required to trigger sediment failure," he said.
Water & Atmosphere also looks at lessons of adaption and resilience from the 2013 drought and reports on an expedition to the Southern Ocean and what that might tell us about climate change.
The magazine is available online at www.niwa.co.nz/publications/wa
