Hawkes Bay Today
  • Hawke's Bay Today home
  • Latest news
  • Sport
  • Business
  • Opinion
  • Lifestyle
  • Property
  • Video
  • Death notices
  • Classifieds

Subscriptions

  • Herald Premium
  • Viva Premium
  • The Listener
  • BusinessDesk

Sections

  • Latest news
  • On The Up
  • Sport
  • Business
  • Opinion
  • Lifestyle
  • Property
    • All Property
    • Residential property listings
  • Rural
    • All Rural
    • Dairy farming
    • Sheep & beef farming
    • Horticulture
    • Animal health
    • Rural business
    • Rural life
    • Rural technology

Locations

  • Napier
  • Hastings
  • Havelock North
  • Central Hawke's Bay
  • Tararua

Media

  • Video
  • Photo galleries
  • Today's Paper - E-Editions
  • Photo sales
  • Classifieds

Weather

  • Napier
  • Hastings
  • Dannevirke
  • Gisborne

NZME Network

  • Advertise with NZME
  • OneRoof
  • Driven Car Guide
  • BusinessDesk
  • Newstalk ZB
  • What the Actual
  • Sunlive
  • ZM
  • The Hits
  • Coast
  • Radio Hauraki
  • The Alternative Commentary Collective
  • Gold
  • Flava
  • iHeart Radio
  • Hokonui
  • Radio Wanaka
  • iHeartCountry New Zealand
  • Restaurant Hub
  • NZME Events

SubscribeSign In
Advertisement
Advertise with NZME.
Home / Hawkes Bay Today

Napier flood indirectly linked to atmospheric river phenomena

Thomas Airey
By Thomas Airey
Reporter·Hawkes Bay Today·
11 Mar, 2021 05:02 PM3 mins to read

Subscribe to listen

Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber?  Sign in here

Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
‌
Save

    Share this article

Two atmospheric rivers in the leadup to November 9 laid the foundation for the heavy rainfall that caused the Napier Flood. Photo / File

Two atmospheric rivers in the leadup to November 9 laid the foundation for the heavy rainfall that caused the Napier Flood. Photo / File

New research points to New Zealand's costliest floods coinciding with "atmospheric rivers", but Niwa says November's flood in Napier was not directly triggered by the phenomena.

Atmospheric rivers are relatively long, narrow regions in the atmosphere – like rivers in the sky – that move huge columns of water vapour in the direction of preceding weather.

Not all atmospheric rivers cause damage, but most - when hitting landfall - trigger a rain event of some sort.

Niwa forecaster Ben Noll and scholar Hamish Prince, who wrote his thesis "A Climatology of New Zealand Atmospheric Rivers" last year, said although there was no atmospheric river present on November 9 when Napier experienced record-breaking rainfall, a foundation for the deluge was laid by two atmospheric rivers that passed over New Zealand in the preceding four days.

"The trigger for the event itself was more likely to be the convergence of low-level winds in the atmosphere, forcing air to rise and causing rain — when there is enough moisture around, as was the case on November 9, the rain can be intense," they said.

Advertisement
Advertise with NZME.
Advertisement
Advertise with NZME.

The research shows that Napier can expect its most frequent and impactful atmospheric river events from November to February.

Another study into atmospheric rivers in the southern hemisphere from the Australian Research Council Centre of Excellence for Climate Extremes included data from Niwa showing that nine of the 10 most expensive floods in New Zealand between 2007 and 2017 coincided with an atmospheric river event over the location where the flooding occurred.

Lead author Kim Reid told RNZ last week that although heavy rainfall is really hard to predict, weather models can pick up atmospheric rivers a lot easier since they are much bigger than an individual thunderstorm.

Advertisement
Advertise with NZME.

"So it's kind of an extra step, going from the model to the river to the rainfall is a lot easier than going from the model straight to the rainfall ... we can basically make a lot stronger prediction of extreme rainfall based on what we know about the bigger weather systems like the atmospheric rivers," she said.

In February, Hamish Prince told RNZ that his study has shown that atmospheric rivers are responsible for the vast majority of extreme rainfall in New Zealand - along with over 50 per cent of all precipitation.

"Understanding what drives these events is fundamental to planning for extreme weather and the management of freshwater resources in New Zealand."

Save

    Share this article

Latest from Hawkes Bay Today

Hawkes Bay Today

Single-vehicle crash in Waipawa leaves one dead

18 May 03:13 AM
Hawkes Bay Today

Budget 2025 will expand access to after-hours healthcare in Wairoa

18 May 02:38 AM
Hawkes Bay Today

Villagers end Mighty Maroons' unbeaten run

18 May 01:17 AM

The Hire A Hubby hero turning handyman stereotypes on their head

sponsored
Advertisement
Advertise with NZME.

Latest from Hawkes Bay Today

Single-vehicle crash in Waipawa leaves one dead

Single-vehicle crash in Waipawa leaves one dead

18 May 03:13 AM

Emergency services responded at 4.05am on Racecourse Rd.

Budget 2025 will expand access to after-hours healthcare in Wairoa

Budget 2025 will expand access to after-hours healthcare in Wairoa

18 May 02:38 AM
Villagers end Mighty Maroons' unbeaten run

Villagers end Mighty Maroons' unbeaten run

18 May 01:17 AM
Premium
‘Not just a body of water’: Wastewater pipe being built under river draws strong opposition

‘Not just a body of water’: Wastewater pipe being built under river draws strong opposition

17 May 05:00 PM
Gold demand soars amid global turmoil
sponsored

Gold demand soars amid global turmoil

NZ Herald
  • About NZ Herald
  • Meet the journalists
  • Newsletters
  • Classifieds
  • Help & support
  • Contact us
  • House rules
  • Privacy Policy
  • Terms of use
  • Competition terms & conditions
  • Our use of AI
Subscriber Services
  • Hawke's Bay Today e-edition
  • Manage your print subscription
  • Manage your digital subscription
  • Subscribe to Herald Premium
  • Subscribe to the Hawke's Bay Today
  • Gift a subscription
  • Subscriber FAQs
  • Subscription terms & conditions
  • Promotions and subscriber benefits
NZME Network
  • Hawke's Bay Today
  • The New Zealand Herald
  • The Northland Age
  • The Northern Advocate
  • Waikato Herald
  • Bay of Plenty Times
  • Rotorua Daily Post
  • Whanganui Chronicle
  • Viva
  • NZ Listener
  • What the Actual
  • Newstalk ZB
  • BusinessDesk
  • OneRoof
  • Driven CarGuide
  • iHeart Radio
  • Restaurant Hub
NZME
  • NZME Events
  • About NZME
  • NZME careers
  • Advertise with NZME
  • Digital self-service advertising
  • Book your classified ad
  • Photo sales
  • © Copyright 2025 NZME Publishing Limited
TOP