Weather: March storm dumps month’s worth of rain in days, winds top 140km/h

A powerful weather system that swept down the country this week delivered extraordinary rainfall totals and damaging winds, with some areas recording more than a month’s rain in just a couple of days.

MetService forecaster Gerard Bellam said the heaviest rain fell in elevated northern areas, as expected, before the system tracked south, affecting much of the country.

“It’s quite big numbers,” Bellam said.

Waimate North Rd outside Kerikeri, Northland, on Friday where 24 hours of rain left the road and paddocks flooded. Photo / David Fisher

The highest totals were recorded in the Coromandel Ranges, where Castle Rock received 412mm of rain between Wednesday and Friday, while the Pinnacles recorded 347mm.

Further south, parts of the Tasman ranges were hit by significant falls, with one location recording 319mm.

At lower elevations, where flooding impacts were more visible, Northland had particularly intense rainfall compared with monthly averages.

Kaitāia recorded 231mm over two days – more than double its typical March total of 96mm.

Flooding affected State Highway 29a, near the Oropi roundabout, on Friday. Photo / Zoe Blake

Kerikeri received 226mm, compared with a monthly average of 137mm, while Whangārei recorded 121mm, slightly above its usual March rainfall.

Tauranga, which experienced visible flooding, was doused with 147mm of rain, well above its monthly average of 98mm.

In Auckland, Mt Albert Grammar recorded 130mm.

The deluge led to widespread impacts, including wastewater overflows that left many Auckland beaches unsafe for swimming after the storm.

Heavy rain on Cameron Rd, Tauranga, this week as wet weather lashed the region. Photo / Letitia Atkinson

Strong winds accompanied the system, particularly ahead of the front as northeasterlies intensified.

The highest gust recorded was 141km/h at a MetService radar site near Kaeo in Northland around midday on Thursday.

Other notable gusts included 133km/h at Cape Reinga and 117km/h at Tūtūkākā Harbour.

The system’s reach extended into the South Island, where exposed eastern areas were also hit.

Banks Peninsula’s Le Bons Bay recorded gusts of 113km/h early Friday morning.

Bellam said the pattern largely matched forecasts, with northern and west-facing areas bearing the brunt before conditions eased.

While the worst of the weather has now passed, MetService says the reprieve may be short-lived.

A spokesperson said Saturday would provide a chance for affected regions to “take a breath” and assess damage, but another band of rain is expected to move over the country late Sunday into Monday.

The next system is not expected to be as severe and will be more short-lived, though it will bring a shift to cooler, more southerly conditions.

Looking further ahead, the coming week is forecast to be calmer and drier overall, with a more settled, autumnal feel.