Snow has blanketed parts of the South Island overnight. Photo / Sharlene McKinley
Snow has blanketed parts of the South Island overnight. Photo / Sharlene McKinley
Forecasters are warning flooding is possible in the South Island to accompany “prolific snowfall amounts” in the coming days, while thunderstorms are possible today for a large stretch of the North Island, including Auckland.
Heavy snow and rain warnings are in place for the South Island, including Dunedin, where snow has been forecast down to 200m.
Snowfall closed State Highways 8 and 80 in the South Island overnight, although SH8 has now partially reopened, according to the NZ Transport Agency.
“Further forecast snow may affect state highways and local roads throughout the Canterbury and West Coast region,” NZTA said early this morning.
UPDATE 6:30AM SH8 is now OPEN from Omarama to Lake Pukaki, the road remains CLOSED on SH8/SH80 Pukaki to Fairlie due to snow, and SH80 Lake Pukaki to Mount Cook. ^JP https://t.co/OFLOFlrORU
— NZ Transport Agency - Canterbury & West Coast (@nztacwc) July 29, 2024
It’s thanks to a dynamic low in the Tasman Sea - featuring a “moisture-rich” cloud band that extends from near Darwin in Australia to New Zealand - which is set to deliver widespread rain and wind this week, forecaster Niwa says.
“Blocking high pressure to the south and north mean that the system will be slow-moving with lots of rain and elevation snow,” Niwa said.
Snow would be heaviest above 500m, with “prolific amounts” expected in the heights of the Southern Alps. “Lesser amounts are likely down to 200m, particularly in Otago.”
Wow - the dynamic low in the Tasman Sea features a cloud band that extends from near Darwin, Australia to New Zealand 🌀
This means that it is moisture-rich.
Blocking high pressure to the south & north mean that the system will be slow-moving with lots of rain + elevation snow. pic.twitter.com/ZuB1o8EVLV
“A slow-moving and heavy band of rain may form over the eastern North Island on Wednesday night,” Niwa said.
So far 16cm of snow has fallen overnight at Mt Cook. Photo / Sharlene McKinley
Severe weather warnings, watches for South Island
A raft of weather warnings and watches have been issued throughout the South Island, including an orange heavy rain warning over North Otago, Dunedin and Clutha, which came into effect at 8pm last night.
MetService forecast up to 55mm of rain to fall through to 3pm on Tuesday and rain was expected to turn to snow above 200m.
“It’s not often we see persistent rain like this in this part of the country and the area does not need large amounts of rain for impacts to be felt. We could see surface flooding, especially in eastern areas of Dunedin,” said MetService meteorologist Mmathapelo Makgabutlane.
The Dunedin City Council last night was warning of damage to trees and powerlines and travel disruption due to surface flooding and slips.
An orange heavy snowfall warning over South Canterbury high country and the foothills south of the Rangitata River lapsed at 4am this morning after 24 hours. Meanwhile a further snowfall warning issued for the hills of eastern Otago, including Dunedin, will remain in effect until 10pm tonight.
The snow level was expected to lower to 300m to 500m overnight Monday and during Tuesday morning – with potentially large accumulations about eastern Otago.
South Island highways are closed and alpine areas have been blanketed in snow overnight. Photo / Sharlene McKinley
Motorists using the Lindis Pass (State Highway 8), Milford Road (SH94), and Crown Range Rd – where as much as 15cm of snow was possible in places above 700m - were also urged to take care.
“This is expected to be a wide-reaching snow event, especially for farmers and road users,” Makgabutlane said.
Niwa said snow would continue in the South Island into Thursday.
Severe gales gusting up to 120km/h are also expected for Westland, Grey and Fiordland regions, with the potential to damage trees, powerlines and unsecured structures. These warnings will remain in effect until Wednesday.
Heavy rain for North Island, thunderstorms possible
Thunderstorms are expected to develop across a swathe of the country over the course of the day, starting with a moderate risk for Buller, western Tasman, Taranaki and Waitomo this morning, MetService says.
“These thunderstorms may be accompanied by localised heavy rain with intensities of 10 to 20 mm per hour.”
Northland and down to the west of the North Island are also at a lower risk of thunderstorms this morning.
The risk increases for the North Island during the afternoon and evening, with Northland, Auckland, Coromandel Peninsula, western Waikato, Waitomo and Taranaki as well as the western Bay of Plenty all at moderate risk through to tonight. Western Tasman is also at moderate risk of thunderstorms this afternoon.
Moderate thunderstorm risk this afternoon and evening for a stretch of the North Island. Image / MetService
Heavy rain of 15-25mm per hour could fall in some areas.
MetService said while rain is on the cards for much of the country this week, the wettest weather was expected in the east of both the North and the South Islands.
“This is a developing situation, and although it’s all happening in the South Island during the early part of the week, it’ll be a good idea for people in the eastern North Island to also have a close eye on the forecast,” Makgabutlane said.