According to the prime minister of New Zealand, Cyclone Gabrielle, which devastated much of the North Island, was a weather phenomenon not seen "in a generation.".
Only the third time in New Zealand's history has a state of emergency been declared by a government led by Chris Hipkins.
The affected areas are home to about a third of the five million people who live there.
As a result of rivers overflowing their banks, many people are now homeless, and some were required to swim from their homes to safety.
From rooftops, other people have been saved.
A quarter of a million people lack electricity. Houses have been completely destroyed by falling trees, and other homes have been carried away and blocked by landslides. .
The North Island's far north and east coast coastal communities have been hardest hit by the storm's damage, with Hawke's Bay, Coromandel, and Northland among the worst affected.
A river that burst its banks has completely cut off communications to one town in the area.
The extent of the damage, according to Hawke's Bay civil defense officials, was beyond their ability to handle. The UK and Australia have both promised assistance.
In Muriwai, west of Auckland, a firefighter was caught in a landslide and is still unaccounted for. Rescue organizations reported that a second firefighter involved was critically hurt.
The BBC was informed by Marcelle Smith that she and her two young children had fled inland on Monday night from their cliff-front home in Parua Bay on the east coast of the North Island.
Her husband stayed back to set up security for their house. On Tuesday, they were still dealing with severe weather and some of the embankments they had built had already been destroyed.
"We are making every effort to protect the things we have devoted our lives to. At this point, man and nature are at war, she told the BBC.
Some Hawke's Bay residents reportedly had to swim out of their homes as water flooded them, breaking through bedroom windows. People have been warned they may experience power outages for weeks.
People were seen waiting for help on rooftops in aerial photographs of flooded areas.
Uprooted trees, twisted streetlight poles, and endless rows of inundated homes are just a few examples of the damage's vast scope.
The anchor cable on a stranded sailor's yacht snapped amid strong winds, and the New Zealand Defense Force released dramatic images of officials saving the man.
According to Mr. Hipkins, the severity and damage we are witnessing have not been seen in a generation.
"As the cyclone intensifies, we continue to piece together a picture of its effects. However, we do know that the impact is both substantial and widespread. ".
To help those impacted by the disaster, he has pledged NZ$11.5m (£6m; US$7.3m) in aid.
The storm was "unprecedented," according to Minister of Emergency Management Kieran McAnulty, who declared the national state of emergency on Tuesday morning.
The declaration of an emergency enables the government to coordinate its response to the disaster. As well as Northland, Auckland, Tairawhiti, Tararua, Bay of Plenty, Waikato, and Hawke's Bay, it has been used in those areas.
Only twice before, at the beginning of the Covid-19 pandemic and after the 2011 Christchurch earthquake, has New Zealand issued a national state of emergency.
Climate change has been blamed by the government for the disaster's size.
Climate change minister James Shaw noted that the severity of the situation was exacerbated by the fact that global temperatures had already risen by 1.1 degrees.
We must stop using justifications for our inaction. We can't bury our heads in the sand on a flooded beach. Action is required immediately. ".
Just two weeks had passed since four people lost their lives in the same area due to unheard-of rain and flooding brought on by Cyclone Gabrielle.
According to the MetService, conditions are anticipated to improve over the next few days, and for some regions of the country, heavy rain warnings have been lifted. Although it has issued a warning, more harm from the wind is still possible.