KEY POINTS:
The north is being battered by rain and high winds as the south starts to emerge from a freezing snap which sent a hospital into crisis mode.
People in Northland were being warned to take care and delay any non-essential travel today as MetService forecasted howling winds and up to one month's worth of rain in 24 hours.
Up to 250mm of rain is expected, and that's likely to be accompanied by damaging easterly winds gusting to 120km/h in exposed areas from the Bay of Islands south to the Auckland Harbour Bridge.
Northern Auckland and the Coromandel Peninsula are likely to receive between 100 and 150mm of rain from late this morning through to Wednesday afternoon, MetService said.
There were reports of rising water levels and some surface flooding in the Bay of Islands this morning where one motorist described conditions as "pretty treacherous".
He said most people appeared to be following warnings to stay inside and not venture onto the roads.
Firefighters were at a flooded house in the Far North near Cable Bay. There has also been storm damage to a house in Omapere, west of Kaikohe.
As rain lashed Auckland this morning, the Coastguard said if boaties had not already checked their moorings, they would probably be taking a risk to do it now.
Inspector Gavin McDonald from the police Northern Communications Centre in Auckland said the weather had deteriorated seriously in Northland and was heading south.
"Take care on the roads and be patient. Watch your distances," he said.
Meanwhile after the big chill in the South, residents are now being threatened with flooding as frozen pipes thawed out.
Southland Hospital was yesterday forced to declare a "mass casualty status" - a term normally used in civil defence emergencies - after it was inundated with patients who had fallen on black ice.
The rate of admissions to the hospital's emergency department ran at five times the normal level with injuries ranging from broken arms, legs, hips and fingers.
Most of the injuries happened when people slipped over on transparent black ice.
Police are advising Southlanders to keep travel to a minimum this morning, at least until things warm up
Hydrologists for the Northland Regional Council say that 200mm to 250mm of rain typically falls on the region for the entire month of July. The MetService says most rain can be expected around Northland's central hills and near the eastern coast.
Regional council hazard management team leader Graeme MacDonald said yesterday that the combination of rain and wind was likely to cause problems and urged people to take special care outside and to delay non-essential travel.
The conditions are likely to lead to surface flooding and cause streams and rivers to rise quickly, and high winds could damage unsecured objects, trees and power lines.
Mr MacDonald said driving was also likely to be hazardous. Farmers should move stock to higher ground and boat owners should ensure their vessels were securely moored.
Far North civil defence co-ordinator Bill Hutchinson said emergency services had been told of the warnings and, with the district council, were on watch. Steady rain was already falling in parts of the Far North last night and the Fire Service operations manager in Northland, Allan Kerrisk, said contingency plans were in hand to move incident control directly into any badly hit area.
MetService weather ambassador Bob McDavitt said the severe weather warning for wind and rain resulted from a deepening low-pressure system in the Tasman Sea which was expected to sideswipe the north today and tomorrow.
The outlook
* Torrential rain today for Northland, northern parts of Auckland and the Coromandel Peninsula.
* Gale-force easterly winds to 120km/h in exposed areas.
- with NZPA, NZ HERALD STAFF
