Jamie was racing to get to work in Waitangi.
Northland Fire and Emergency received more than 200 callouts overnight.
A massive low just off the coast of the country "isn't going anywhere in a hurry", forecasters warn.
Extra response teams have been rostered in preparation, power company Vector says.
The twister was one of three to occur in the last 24 hours.
Mangawhai locals have reported seeing street signs and debris flying.
Strong winds have blocked SH25 in Taranaki, while a boat has overturned in the Coromandel.
But the further south you go, the less drenched you'll get.
The rain is moving down the country - but forecasters warn it'll be a bit "hit and miss".