Snow ahead as rain pounds south

03:50, Aug 08 2012
State Highway 1, south of Timaru.
FLOODED: State Highway 1, south of Timaru.

Rivers are rising as rain pounds parts of the country, and snow is forecast to be on the way for some mountain passes.

South Canterbury and Marlborough hardly had time to dry out from last week's drenching before another nasty weather system got the areas in its sights.

Heavy rain fell in Marlborough during the night, causing the Omaka River to rise and forcing the closure of a road that had just reopened yesterday after last week's flooding.

Early this morning Marlborough District Council said the river was continuing to rise.

The council was already facing six months' of work to fix the damage from last week, most of which was along the Omaka with fences swept away, road seal lifted, the stopbank holed and at least two vineyards flooded.

MetService said heavy rain was likely today and tomorrow along the Kaikoura coast and in the ranges. In the 27 hours from 9am today 130mm to 180mm could fall in the ranges, with 90mm to 130mm on the coast.

In South Canterbury steady rain was reported to have been falling through the night.

Environment Canterbury duty flood control officer Tony Henderson said the rain had mostly been falling on the coast and plains, rather than in the foothills as MetService had expected.

"We're getting quite a lot of rain around Timaru and the plains area, but the rivers aren't rising quickly," he said.

"If it does get back into the hills, rivers will rise very quickly because the ground is saturated."

The rain falling on the coast and plains would cause surface flooding and affect roads.

MetService said it expected a further 60mm to 90mm of rain to fall in the foothills in the 12 hours from 9am today.

The 36 hours of heavy rain last week caused extensive damage to rural bridges and surface flooding throughout low-lying areas of South Canterbury.

Today's heavy rain was the result of a low lying east of central New Zealand, directing a moist southeast flow over eastern parts of the South Island.

MetService said snow was expected to settle on higher parts of the Lindis Pass road this morning, with 1cm to 2cm accumulating on higher parts of the road between 9am and noon.

It expected rain to turn to snow overnight on the Porters Pass and Arthurs Pass roads.

At Porters 3cm to 6cm was expected to accumulate near the summit in the eight hours from 10pm, while at Arthurs Pass 1cm to 2cm was expected.