Beach-goers gather at Whangamata in January 2018, during a severe nationwide marine heatwave. Photo / Lesley Staniland
Beach-goers gather at Whangamata in January 2018, during a severe nationwide marine heatwave. Photo / Lesley Staniland
Hamilton and some other Waikato centres have been included in a summer heat alert trial launched this week to warn when an extremely high temperature - record or near record - is expected.
The trial is an expansion of the first phase last summerby MetService in partnership with the University of Waikato and the Institute of Environmental Science and Research.
MetService meteorologist Georgina Griffiths says: “With extreme heat events worsening in response to human-induced climate change a national heat alert system is really important. This trial is an important step towards that.
“Until March 30, we’re doubling the locations the alerts are provided for and refining the alert thresholds.”
Extreme heat during summer can be draining and affect people’s daily lives – especially their health and well-being. International research shows that extreme heat and heatwaves can cause illness and death, but effective planning and actions can reduce its effects on health, a statement about the trial launch said.
The heat alerts will cover 44 urban areas for which MetService writes a daily forecast. An alert will be triggered by an extremely high temperature (record or near record) or when a run of very hot and humid weather is forecast. Hot, humid weather is typically less well tolerated than hot, dry weather.
A mock heat alert notice shows how it would appear on metservice.com.
The North Island urban areas covered by the trial are: Kaitaia, Paihia and Russell, Whangarei, Dargaville, Auckland, Whitianga, Thames, Hamilton, Tokoroa, Te Kuiti, Tauranga, Whakatane, Rotorua, Taupo, Taumarunui, Gisborne, Napier and Hastings, Dannevirke, Masterton, New Plymouth, Whanganui, Palmerston North, Levin, Paraparaumu and Wellington.
Heat alerts will appear on metservice.com, and in the new year on the MetService weather app, in a banner and as part of the daily forecast for each location.
If a heat alert is triggered, people should take precautions, such as keeping hydrated, seeking shade, checking in with vulnerable people/children and looking after pets and livestock.
People are also advised to use the alert information to inform their decisions, for example not going for a long run or having employees outside picking fruit.
“New Zealand, unlike countries such as the United Kingdom and Australia, does not have a national heat warning system. This heat alert trial is an opportunity to look deeper into the New Zealand requirements of such a warning system,” says Griffiths.
The criteria for the alerts were developed by meteorologists at MetService and senior lecturer in climate change, Dr Luke Harrington, at the University of Waikato
Harrington says: “The thresholds for the alerts are localised to the area in question – the threshold for Northland or Gisborne will differ from that used in cooler areas, such as Westland.
“Thresholds to trigger alerts have been set very high, in part to ‘future proof’ this type of alerting against a background of continued warming due to climate change.”
Harrington recently undertook a synthesis of extreme heat in New Zealand. Results showed the hottest days of the year have warmed by more than .5C over the past 20 years for many populated regions of the country, a rate that exceeds average annual changes across the country.
Griffiths adds: “We’ve had some record-breaking summers in recent years. These alerts are for extreme heat and we’d only expect to use them occasionally. How often the alerts are issued, of course, depends on the type of summer we get. December has started off cooler than usual so far, but La Nina should kick in, producing above-average summer temperatures, overall.”
The South Island urban areas covered in the trial are: Motueka, Nelson, Reefton, Westport, Greymouth and Hokitika, Blenheim, Kaikoura, Christchurch, Ashburton, Timaru, Oamaru, Dunedin, Alexandra, Gore, Invercargill, Mt Cook, Wanaka, Queenstown and Milford Sound.
MetService is New Zealand’s National Meteorological Service. A team of 60 trained operational meteorologists, qualified to the World Meteorological Organisation training standards, provide New Zealand’s forecasts and official severe weather watches and warnings service.
