Tornadoes can form anywhere there are thunderstorms.
From the NZ Herald report (in full
here):
"Albany's second killer blow
Yesterday's tornado is the second fatal twister to hit Auckland's North Shore area in 20 years.
In May 1991, a tornado hit Albany, lifting roofing iron from homes and destroying a small church on the south-western side of the suburb. One man died when debris spread by the tornado hit him while he was driving a bulldozer.
Damaging tornadoes seem to hit Auckland every two or three years and other previous incidents have included damage to buildings and power lines.
One of New Zealand's worst tornadoes was at Frankton, Hamilton, in August 1948, when three people were killed.
Seven people were badly injured and damage to property was heavy.
Buildings were lifted from their piles, chimneys were snapped off, houses lost their roofs, trees uprooted and power and telephone lines were left hanging in the streets.
Reports at the time said the air was filled with flying corrugated iron, branches of trees, timber and other debris.
Another three people died in a tornado near Waitara, Taranaki, in 2004."
yikes i would like to see one for real one day 
