Police warning as cold blast forecast
Motorists have been warned to drive to the conditions as a blast of cold, wet weather approaches Canterbury.
MetService forecaster Daniel Corbett said temperatures over the weekend would be mild, with Saturday expected to reach 21 degrees Celsius.
Sunday would hit 19C, but a southwest change later in the day would bring rain and see temperatures drop.
Corbett said that on Monday, Tuesday and Wednesday, temperatures would reach the low teens.
There was also the possibility of frost on Tuesday and Wednesday.
MetService expects heavy rain in South Westland and Fiordland tomorrow.
That was likely to spread to Otago and Southland on Sunday, with snow possibly lowering to 400 metres, and heavy falls possible at higher levels.
Senior Sergeant Phil Newton, of the Canterbury Highway Patrol, said wintry weather significantly increased the chance of a driver having a crash.
Last year, 33 people died on Canterbury roads, 10 of those between May and August.
"The biggest factor in the winter road toll is motorists failing to drive to the conditions. Our most important message to all drivers is to slow down whenever the weather turns bad," Newton said.
"Drivers also need to increase their following distance behind other vehicles to ensure they have a better chance of reacting quickly enough to hazards or difficult situations."
An average vehicle will take between 28 and 35 metres to stop when travelling at 50kmh on good roads and with good driver reactions.
At 100kmh, the stopping distance increases to between 98m and 112m.
"And if a driver is going too fast in the wet, where visibility can be limited and traction is reduced, these stopping distances increase even further," Newton said.
Drivers should ensure they had an unobstructed view through their windscreens and windows by clearing ice and condensation.
"I have already seen one driver leaning out of his side window while driving in an attempt to get good visibility,'' he said.
"The stupidity of some people to place themselves and other road users in danger of having a crash is amazing."
Newton recommended motorists check their tyres had sufficient tread, brakes worked correctly, all lights worked, windscreen wipers were in good condition and snow chains were on board if travelling over the passes.