Cyclone Debbie rainband to wreak havoc in Northland

Commuters heading home yesterday as steady rains settles over Whangarei. Photo/John Stone

As weather experts and Civil Defence watched a huge rainband move west toward Northland one of their biggest concerns was whether the already wet ground could soak up much more water.

When early March's rainstorm dumped its load on a drought-dry region, it caused some surface flooding and minor landslips but the ground acted much like a sponge.

Last night's heavy rain and thunderstorm alert came with an added warning there could be more slips of sodden land if the forecast rainfall concentrations occurred.

Yesterday morning MetService's heavy rain warning predicted 120mm to 180mm of rain for the region over 30 hours until 9pm today.

Further, MetService said more than 180mm could fall in the hills in Northland's north and east, with peak intensities of 25mm to 45mm an hour, and thunderstorms possible.

However, by edition time yesterday the region's rainfall had not been anything like as heavy as predicted.

Northland Civil Defence Emergency Management Group (CDEM) spokeswoman Victoria Randall said people should have taken action such as clearing gutters and drains after last month's storm.

Until about 3pm today they should also minimise travel and check road conditions such as the AA Roadwatch website, local radio or social media.

"Although this weather system is forecast to move away quickly [this evening], Northland received double the expected amount of rainfall during March," Ms Randall said.

"With soil conditions close to saturation, any rain will run straight off and rivers will respond immediately to the intense rain. Surface flooding and slips are also likely."

At edition time, MetService had not changed its weather warnings; an update was due at 9pm last night.

Civil Defence said it would update the public as required, including through the Northland CDEM Group's Facebook page - www.facebook.com/civildefencenorthland or people can get the latest weather information from www.metservice.com.