The national weather authority has revealed a rare warning issued only for “significant impact” events could have been delivered a day earlier as Cyclone Gabrielle struck the country.

MetService chief meteorologist Chris Noble gave evidence during the second day of a coronial inquest into the deaths of 18 people during Cyclone Gabrielle and the Auckland Anniversary floods of 2023.

Coroner Erin Woolley is holding the hearings.

Ex-Tropical Cyclone Gabrielle tore through the Hawke’s Bay region between Sunday, February 12, and Wednesday, February 15. The worst impacts were felt on Monday night (February 13).

Asked by counsel assisting the coroner, Matthew Mortimer-Wang, whether there were grounds to issue a red warning on Sunday morning, Noble acknowledged that hindsight was a wonderful thing.

‘Red warning could’ve been justified on Sunday’

He said the fact there were discussions around a red warning on Sunday morning means it could have been issued to the public.

“A red warning could’ve been justified on Sunday,” he said.

The devastation of Cyclone Gabrielle in Wairoa captured from the air on February 14, 2023, looking over North Clyde and Carroll St, towards Frasertown Rd. Photo / Hawke’s Bay Civil Defence Emergency Management

“I think it could’ve – bearing in mind the event we’re discussing is a significant ex-tropical cyclone passing through the northeast of the North Island.”

A report showed a meaningful upgrade from orange to red could have been made when the first warnings were issued at 10.06am on Sunday, February 12.

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It was revealed the MetService severe weather team had concerns about the need for a red warning and discussed this with the Hawke’s Bay Regional Council hydrology team that Sunday morning.

A severe red heavy rain warning was issued on Monday, February 13, 2023, as Cyclone Gabrielle tore through Hawke's Bay. Image / MetService

“The hydrologists were opposed to a red warning being issued – citing high confidence in their flood modelling, which indicated no major concerns,” the report read.

It also showed that engagements between the MetService severe weather team and the Hawke’s Bay Regional Council were limited to the council’s hydrology team.

“And it remains unclear to what extent MetService concerns were passed on to other relevant teams within the council or the wider CDEM [Civil Defence Emergency Management] Group,” the report read.

“In summary, the warning issued at 10.06am on Sunday, February 12, should have been red and had the severe weather team chosen not to seek the agreement of Hawke’s Bay Regional Council, it probably would have been.”

A car juts out of silt on Shaw Rd, Esk Valley, after Cyclone Gabrielle wreaked havoc in February 2023. Photo / Hawke’s Bay Today

MetService eventually issued a red heavy rain warning on the Monday afternoon, with an update posted by the Hawke’s Bay CDEM Group at 4.30pm that day.

A key finding in the report showed forecasters were strongly influenced by council hydrologists’ perspectives.

“This may have led to insufficient emphasis on broader considerations of potential impacts for event messaging and communication.”

‘We are responsible for the warning’

Noble said they were very cautious about issuing red weather warnings as overuse could lead to public complacency.

“You’re perceived to cry ‘wolf’ too many times,” he said.

“We don’t want to overdo the number of red warnings. But when they need to be issued, they should be.”

A spokesman for Hawke’s Bay Regional Council said it disputed the framing of its interactions with MetService as it being “opposed” to a red warning being issued.

While HBRC staff may be asked for their opinions on the possible impacts of forecast rain, it was “not our role” to take a position on whether MetService’s warnings ought to be upgraded, the spokesman said.

He said council was due to give evidence at the inquiry in October.

Noble acknowledged the Cyclone Gabrielle weather event, as well as the Auckland Anniversary flooding incident, had resulted in lessons for how it does things.

Ultimately, it was MetService’s decision whether or not to go with a red weather warning, Noble said.

“We are responsible for the warning.”

Asked later whether anything had changed around MetService’s decision-making for warnings since 2023, Noble agreed there had been.

“There’s a much more heightened awareness that MetService owns that decision and I would say it is more willing to issue a red warning.”

The inquest continues this week. Others set to give evidence include those from the National Institute of Water and Atmospheric Research, Fire and Emergency New Zealand and the National Emergency Management Agency.

Family members of those who died are also due to give evidence over the coming weeks.

• This article has been updated to include a comment from Hawke’s Bay Regional Council, which disputes that it was “opposed” to the red warning and is due to give evidence to the inquest in October.