Flooding has swept through many Napier streets, prompting evacuations, rescues and causing widespread damage, and a local state of emergency has been declared.
Wild weather is hammering Napier, with slips, flooding and leaking roofs causing chaos. Firefighters have been called to assist flooded buildings, and power is out to many properties.
People were being urged to stay inside, as long as it was safe to do so, and not to drive or to come into contact with the floodwaters, which could be contaminated.
Those who need assistance were asked to call 111 for help, and not Napier Fire Station.
Napier Mayor Kirsten Wise has declared a local state of emergency in Napier. Updates, including road closures, are being published on the Hawke's Bay Emergency Management website.
MetService warned the rain could continue until late tonight, and more is expected tomorrow.
Hawke's Bay Emergency Management controller Ian Macdonald said at least 30 people had been evacuated due to what he called a one in 100 year event.
Rescues and assisted evacuations were being carried out on a case-by-case basis, depending on the risk presented by the flooding and land slips, but he said if people felt unsafe where they were they should self-evacuate.
Fire and Emergency NZ Area Manager Ken Cooper said there were 14 urban and rural crews responding to more than 150 calls for assistance, mostly from people in Napier city.
About half of the calls for help had been responded to, and workers expect to continue through the night. Calls to people who need hospital treatment, the elderly and those in danger were being prioritised.
"We are triaging calls for assistance for homes flooding and roofs leaking, and have removed some elderly from their homes to stay with relatives," Cooper said.
Hawkes Bay's Urban Search and Rescue team is assessing 16 properties at risk from slips on Napier Hill, and checking people still there were safe, he said.
"There are people still in those houses, so that's really our primary concern, to do a rapid assessment."
Photos posted online showed deep water in many streets, with cars and a shipping container floating in streets inundated with floodwaters.
A man helping with rescue efforts told RNZ he had to fight through chest-deep water to get to houses.
On Facebook community pages people have warned that motorists driving fast through flooded streets were sending wake into flooded buildings. Others had offered their houses as safe places for people to take refuge if they could't get home, or had to leave their home.
People who have evacuated have been asked to stay with friends and family where possible, but an evacuation centre has opened at Kennedy Park Resort camping ground in eastern Napier.
Power outages were affecting nearly the entire city, and the Unison power company said more than 3000 customers had no electricity. The company's website said the problems weren't expected to be resolved until Tuesday afternoon.
A local 4WD group posted online offering to help rescue people stuck in buildings in the city, with one saying he had to retreat after rescuing one person, as the water was already at bonnet level.
Some Napier schools have said they will be closed on Tuesday due to the flooding.
Forecasters warned Hawke's Bay residents that up to 130mm of rain could cause surface flooding and driving hazards from this afternoon, when rainfall rates could reach up to 40mm/h during thunderstorms. With "another burst of heavy rain possible on Tuesday."
Brewster Street 17-year-old Jesse Pether said a slip outside his house had completely blocked the road, and sent floodwaters into a neighbouring house.
"I had my back turned and it sounded like thunder crashing, and it was this slip from two doors down just across the road - trees falling, poles and mud everywhere, and then water flooding it up, like a huge pool."
Napier South resident Amanda said the amount of water was daunting.
"It's just as though there's a river going down the road, and I've lived here off and on since I was three, I've never seen anything like it."
RNZ Reporter Tom Kitchin told RNZ's Checkpoint he had been trapped in his office during the evening by flooding outside the building and torrential rain.
"The rain is very heavy... I don't want to go outside because I know a whole lot of water will come into the office, it's that bad at the moment. I can see the roads are flooded all over.
"Fire and Emergency NZ are quite busy... they're just getting multiple calls. A lot of buildings have been flooded, there's a lot of surface flooding, and I'm just hearing sirens blaring all the time at the moment."
Hawke's Bay Medical Officer of Health Nick Jones said floodwaters could carry bugs that cause disease from the ground surface and sewerage systems.
Dr Jones said people shouldn't eat any food that has been in contact with flood waters, and should avoid contact with the water.
️ Record breaking rainfall in Napier ️— NIWA Weather (@NiwaWeather) November 9, 2020
2nd wettest day on record (since 1870): 237 mm (and counting) since 9am
423% of the November normal in a single day
Wettest hour on record (since 1995): 54 mm between 5-6pm pic.twitter.com/TIF4IYIJem
Napier City Council said by 8pm Monday more than 110mm of water had fallen at Napier Airport since the start of the day, with about 100mm falling between 12pm and 8pm.
"Due to the significant amount of rainfall, manhole covers were beginning to lift, and the escaping water would have caused a public health risk.
"So the decision was taken to release pressure from the wastewater network and discharge wastewater at 5:45 pm this evening, into the Purimu stormwater stream, which flows out to sea through the Ahuriri Estuary."
The regional council environmental team will monitor the stormwater network as well as at several other locations for a number of days, to trace the effects of the discharge.
The city council said the deluge was causing problems for the wastewater network, but the emergency discharge to the Ahuriri Estuary should relieve some of that strain.
Residents have been asked to avoid flushing toilets, and hold off using showers, dishwashers or washing machines, to try to relieve stress on the network.
A restaurant open only for four months has been completely flooded in Emerson Street.
Andrew Beck owns Rock My Belly, along with his wife, and said the deluge started heavily just after 4pm.
"It came through everywhere. The fire brigade said 'there's nothing that can withstand this amount of water', and it just came through and flooded the entire place, the brand new flooring, everything.
"We've only been open four months, we made it through Covid, and now - torrential rain."
MetService Heavy Rain warnings
MetService warned heavy rain could fall in Hawke's Bay south of Wairoa, and Gisborne until 1am Tuesday.
Thunderstorms could bring intense downfalls from the afternoon onwards, and could reach 25mm/h to 40mm/h in thunderstorms.
On top of what had fallen during the day, they said a further 70 to 100mm of rain could fall in the ranges in the evening and into the night, with 40 to 70mm elsewhere.
Forecasters warned that more heavy rain could be coming on Tuesday, too.
Heavy rain and thunderstorms could also strike Tararua district between 7pm tonight and 7am tomorrow, with up to 100mm of rain possible and downpours up to 25mm/h.
Wairarapa and the eastern hills of Wellington could expect heavy rain from 9pm Monday to 11am Tuesday, with up to 110mm expected in some parts, and intensities up to 20mm/h.
"A front in the east of the North Island should sink southwards during today and tomorrow morning, delivering heavy rain," MetService said on Monday.
"On Tuesday, a low is forecast to track east across the upper North Island, delivering rain to many places."
Heavy rain could hit the Coromandel Peninsula on Tuesday from 6am, and the Bay of Plenty from 11am.