Relatively mild temperatures today could be misleading for South Island road users as potentially heavy snowfalls loom from tomorrow.

MetService has strong wind watches in place for parts of the South Island today with northwesterly winds potentially approaching severe gale in exposed places in the Canterbury high country. These warmer ‘Foehn’ winds are expected to push temperatures up to a comfortable 16 deg C in Christchurch today.   

Those driving in gale-force winds are urged to take extra care, especially those operating high-sided vehicles, towing vehicles and motorcycles.

From tomorrow, the weather is expected to take a colder turn, with MetService this time predicting strong southerly winds approaching severe gales for Coastal Otago, Coastal Southland, Southern Fiordland and Stewart Island. Christchurch, Banks Peninsula, and the Canterbury Plains about and east of Lincoln, may get southwesterly winds approaching severe gale in exposed places tomorrow night. 

This cold air from the southerly flow is expected to move up the island, and forecasting provided to New Zealand Transport Agency Waka Kotahi (NZTA) suggests heavy snow could fall on Friday, in places such as Canterbury’s alpine passes, with 10-20cm possible about and west of Arthur’s Pass, affecting State Highway 73, and in the Lewis Pass area, affecting State Highway 7.

Snowfalls may fall to as low as 200m elevation on Saturday, while the Mackenzie Basin is expected to get lesser amounts.

With snow also forecast for State Highway 94 near Milford Sound tonight, the highway is due to close at 5pm from the Lower Hollyford Road turnoff to The Chasm. This section of SH94 is expected to reopen late tomorrow morning, with potential ongoing snow showers causing further disruptions throughout the day.

Road users are encouraged to plan ahead by checking the weather and roading conditions. NZTA may close other state highways where the snowfall puts people at risk. People are encouraged to carry warm clothing, food and water with them in case of travel delays or detours.

In winter driving conditions where traction is affected, motorists are urged to reduce their speeds, increase their following distances, and avoid sudden braking or turning movements and stay as visible as possible.