Flooding on State Highway 10 at Kāeo during Cyclone Tam earlier this month. Photo: RNZ/Peter de Graaf
NZTA Waka Kotahi is urging drivers to take extra care at four crunch points on Northland's state highways as more heavy rain is expected to batter the region later today.
The roading agency said flooding was possible on State Highway 1 at Rangiahua, west of Ōkaihau, and at Whakapara, north of Whangārei, as well as on State Highway 10 at Kāeo.
More slips were possible on State Highway 1 at Mangamauka Gorge, south of Kaitāia, which was still down to one lane after Sunday's big slip closed the road for more than 24 hours.
Temporary road surfaces on State Highway 1 at Whakapara and Akerama, where major road rebuilding projects were underway just north of Whangārei, could also be affected by heavy rain.
NZTA warned that large potholes could form anywhere and floodwaters could hide branches or other hazards.
Flooding just 30cm deep could be enough to sweep away vehicles, the agency said.
A MetService heavy rain watch for all areas north of Whangārei was forecasting heavy rain, possible thunderstorms and localised downpours from 10am today until midnight.
Northern and western parts of the region were likely to be worst affected.
MetService this morning also declared a severe thunderstorm watch for Northland, with downpours of 25-40mm/h possible, from 10am until midnight.
Heavy rain, snowfall warnings
MetService also issued orange heavy rain warnings for Canterbury and the Tairāwhiti region, north of Tolaga Bay, from Wednesday.
The MetService warnings cover Banks Peninsula and the region north of Amberley, as well as the Kaikoura Coast and ranges.
There are also road snowfall warnings for the Porter's and Arthurs Passes.
Christchurch and Canterbury south of Amberley is under a heavy rain watch.
The forecaster said 70 to 100 millimetres of rain is expected in Tairawhiti in the 12 hours until midnight Wednesday.
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