Stormy weather conditions forecast for overnight has Northpower encouraging its electricity consumers to be prepared.

A lightning strike was the probable cause of an outage that knocked out power to 139 consumers in the Mangawhai area about 3.35pm today. Power was expected to be back on by 6.30pm.

Public Affairs Manager Steve Macmillan said Northpower was gearing up for a potentially rough few days with additional lines crews, arborists and telephonists on stand-by.

"After a sustained period of extremely dry conditions, the heavy rain that is being forecast for Northland could cause slips which could take out power poles. There is also increased likelihood of land movement causing trees to damage powerlines and if flooding hits we could be delayed getting to some areas of Kaipara and Whangarei," Mr Macmillan said.


"We would encourage people to be prepared for possible outages by having torches and battery powered radios at hand, mobile phones charged, fresh water available and gas cooking facilities ready."

Outages or potential causes of outages could be reported to Northpower faults on 0800-10-40-40.

If there were outages overnight crews would do their best to attend to what they could. However, if any major repairs were required they would be made in daylight.
He warned people to stay clear of downed lines.

MetService issued a severe thunderstorm warning at 4pm today with the weather radar detecting severe thunderstorms near Rawene, Broadwood and Kohukohu.

These severe thunderstorms are moving towards the south and are expected to be accompanied by very heavy rain.

Very heavy rain can cause surface and/or flash flooding about streams, gullies and urban areas, and make driving conditions extremely hazardous.

The Ministry of Civil Defence and Emergency Management advises that as storms approach you should:

- Take shelter, preferably indoors away from windows;
- Avoid sheltering under trees, if outside;
- Move cars under cover or away from trees;
- Secure any loose objects around your property;
- Check that drains and gutters are clear;
- Be ready to slow down or stop, if driving.

During and after the storm, you should also:
- Beware of fallen trees and power lines;
- Avoid streams and drains as you may be swept away in flash flooding.