Satellite image in the visible spectrum from the geostationary Himawari 8 satellite showing cyclone Gabrielle as it hits New Zealand 1.30pm 23 February 2023
picture supplied
credit: JMA
Satellite image in the visible spectrum from the geostationary Himawari 8 satellite showing cyclone Gabrielle as it hits New Zealand 1.30pm 23 February 2023
picture supplied
credit: JMA
“Insane” footage from space of Cyclone Gabrielle’s full journey from near Queensland, Australia to New Zealand has been shared, highlighting the devastating path it’s taken over the past week.
The extratropical cyclone could be seen forming in the Coral Sea, northeast of Townsville, gathering strength and making its way towards Brisbane and the Gold Coast in a southwesterly direction.
Cyclone Gabrielle is then seen boomeranging off the coast close to Rockhampton before making a shift southeast, through the path of Norfolk Island, and heading straight for New Zealand.
The footage then shows the cyclone hitting Auckland, including Great Barrier Island, the Coronmandel, Bay of Plenty, the East Coast and Hawke’s Bay, which caused widespread flooding and devastation.
What caught the eye is how Cyclone Gabrielle made a sharp pivot towards Great Barrier, followed by a pinball-like bounce to the east.
The full journey of Cyclone Gabrielle from formation near Queensland, Australia to extratropical cyclone near New Zealand. Photo / Zoom_Earth / Instagram
This shift - which began Monday morning - contributed to intense levels of rainfall across many parts of the North Island that led to widespread flooding, landslides, damaged and crumbled roads, broken bridges, and houses ripped off their foundations.
NZ Herald science reporter Jamie Morton explained meteorologists are at pains to point out that, while we refer to Gabrielle as a cyclone, it ceased to be one in the sense that most of us understand them after it underwent “extra-tropical transition” on its way here.
Having met colder waters and stronger upper-level winds on its southward path across the Tasman Sea, Gabrielle had morphed into a different weather system entirely, and not one necessarily any weaker.
“It’s not determined by tropical dynamics anymore - it’s not really-warm waters giving it all of its convection and lowering the pressure – it’s now driven by the upper atmosphere,” MetService forecaster Lewis Ferris explained.
What was going on up at that level, tens of kilometres above the Earth’s surface, happened to explain that abrupt dog-leg turn in the system’s eastward course.
Niwa meteorologist Ben Noll singled out a piece of vorticity – “basically, spin” – in the middle part of the atmosphere that was coming in from the central Tasman Sea and getting wrapped around the cyclone’s circulation.
Aerial photographs show the extent of damage caused by a landslip at Muriwai. Photo / George Heard
“This is causing two things to happen: one, the merging of these two pieces of energy is causing the system to intensify; two, it squeezes it, a little like a fist, and also tugs it back slightly to the west,” he said.
It was also during this process, in tandem with a vigorous sub-tropical jetstream, that Gabrielle’s central pressure plummeted to near-record values on Wednesday morning.
Meteorologists have tallied dramatic weather totals, declaring this extratropical cyclone is a history-maker.
Between midnight Sunday and 11am Tuesday, a whopping 568mm had fallen at Raparapaririki in the ranges of Tairāwhiti, where scenes of heavy flooding have emerged amid a communications blackout.
Extensive flooding at Awatoto seen from above the Napier Golf Course. Photo / Photography by Corena
Those numbers were approaching some of the incredible values recorded in 1988′s Bola – one of the costliest cyclones in New Zealand’s history – in which 419mm fell at Te Puia in 24 hours, while Glenross Station recorded a mammoth 917mm over four days.
“We’ve had stations in that region recording half a metre [of rainfall] – so we’re talking about a shorter duration than Bola, but just as intense,” Niwa forecaster Ben Noll said.
At Niwa’s Fernside station in the Gisborne district, 375mm fell between Monday and Tuesday morning, while 345mm was recorded at Whangarei, where yesterday was the city’s wettest February day on record.
“Since Sunday, Whangarei is now sitting at three and a half times its monthly normal.”
Elsewhere in Northland, the climate station at Trounson measured 305mm over that one-and-a-half-day period, while the Brynderwyn Hills were saturated with 299mm.
At Napier – where emergency services ordered the evacuation of multiple suburbs on Tuesday – the 175.8mm of rainfall registered at the city’s airport in the 24 hours from 9am Monday proved its second-wettest February day since 1950, and eclipsed the 56mm usually recorded there in an average February.
Other standout totals included the 200mm that a station at Maunganui, north of Napier, recorded in just 12 hours to 7am Tuesday.
In that same period, climate stations measured 191mm at Pukeorapa southwest of Gisborne, 160mm in Waitakere in Auckland, 152mm in southern Coromandel’s Golden Valley and 133mm at Wallers, northwest of Auckland.
“At Western Springs, we saw two times the monthly normal in just under 24 hours.”
Gabrielle has also brought seriously strong wind speeds.
“Wind gusts over 140km/h have been recorded at many exposed coastal locations, but urban areas have been affected too, with New Plymouth airport gusts reaching 128km/h, with wave heights close to 11m recorded off the coast of the Bay of Islands,” MetService meteorologist Andrew James said.
The highest peak wind gust measured by one of Niwa’s stations was at Dargaville, measuring 127km/h, while MetService had observed gusts as powerful as 140km/h in Northland, along with 135km/h in the Hauraki Gulf.
Today, a body has also been recovered in the area where rescuers were searching for a missing firefighter in Muriwai after a landslide brought down houses, trapping two people.
At least 10,500 people are displaced from their homes across the North Island, including 9000 across Hawke’s Bay and 3000 people are sheltering in Civil Defence centres. People are struggling today to come to terms with the incredible loss of life, property, animals, roads and crops.
More than 300 residents have been rescued from rooftops and waters since floods inundated the region, cutting off roads, bridges and isolating communities.
Two people are confirmed dead, one woman died after a landslide on her property in northern Hawke’s Bay and a body was found washed up at Bay View Beach, north of Napier.
