Trees torn down in the Clutha region after Thursday's wild weather. Photo: Supplied / Clutha District Council
Labour Day holiday plans could be thrown into disarray, as a major storm system bears down on the country, bringing heavy rain, severe gales and snow to several regions.
NEMA chief executive Dave Gawn said MetService has now issued orange and yellow warnings across both islands, and advised travellers to take the conditions seriously, as they head home from the long weekend.
"MetService have issued warnings for rain, wind and snow, and it's essential that people factor these into their travel plans," Gawn said. "Plan your journeys, pack extra supplies in case you get stranded, and if it's looking really hairy, consider delaying your travel if you can.
"Check for closures before you hit the road, be on the lookout for slips and debris, and never drive through floodwater."
Gawn said the agency had activated the National Crisis Management Centre in the Beehive to co-ordinate support across regions already hit by last week's severe weather. Extra personnel and generators have been moved into Southland and Clutha, with rural recovery assistance being prepared.
"Many communities are still picking up the pieces after Thursday's storms and forecast severe weather will be a setback to clean-up efforts," he said.
Widespread warnings of heavy rain, gales, and snow
MetService said an active low-pressure system in the Tasman Sea would cross New Zealand on Monday and Tuesday, affecting almost every part of the country.
Severe weather watches and warnings are now in force, and forecasters warn that conditions may worsen, as the system strengthens.
"An active low-pressure system in the Tasman Sea moves across New Zealand during Labour Day and Tuesday morning, bringing heavy rain and strong winds to many regions, including heavy snow for the Canterbury High Country," MetService said.
Disruption likely for holiday travel
Forecasters say the timing of the storm - hitting as people return from Labour Weekend breaks - could cause widespread travel delays on both roads and flights.
A Heavy Rain Watch is in place for the eastern ranges of the Bay of Plenty from 10pm Monday to 10am Tuesday, with forecasters warning rainfall could reach warning levels.
Strong wind watches cover much of the country, with the worst conditions expected from Sunday evening through Monday night:
Heavy Rain Warnings (Orange) are in place for:
- Central North Island hill country (southern Waikato to Tongariro National Park): 5pm Monday to 5am Tuesday. Expect 60-90mm, with thunderstorms and peak intensities of 25 mm/hr.
- Ranges of Grey and Buller, and Tasman west of Motueka: 8am to 10pm Monday, with 80-120 mm expected.
- Westland north of Haast: 10pm Sun to 7pm Monday, with 150-200 mm forecast.
- Canterbury headwaters (north of Arthur's Pass/SH73): 6am to 6pm Monday, 90-120 mm near the divide and heavy snow higher up.
- Tararua Range: 2pm Monday to 5am Tuesday, with up to 150 mm possible.
- Taranaki Maunga: 2pm Monday to 3am Tuesday, with 100-150 mm expected.
Heavy Snow Warning (Orange):
- Canterbury High Country south of SH73: From 2-9pm Monday, expect 10-15cm above 500m and up to 30cm above 800m around the Mackenzie Basin.
Strong Wind Warnings (Orange):
- Wairarapa and Tararua District: 2-11pm Monday, northwest gusts up to 120 km/h.
- Wellington: 2-11pm Monday, northerlies gusting to 130kmh in exposed places.
Strong Wind Watches (Yellow):
- South Taranaki to Taihape (including inland Whanganui): 3-10pm Monday, with north to northwest winds possibly reaching severe gale in exposed places.
- Hawke's Bay and Gisborne (especially near the ranges): 6pm Monday to 2am Tuesday, with damaging gusts likely.
- Nelson, Tasman and Marlborough (north of Cape Campbell): 2-10pm Monday, where north to northwest winds may approach severe gale.
- Canterbury High Country (north of SH73) and southern Marlborough: 8pm Sunday to 5pm Monday, easing from the south in the afternoon.
- Canterbury High Country (south of SH73): 8pm Sunday to 6am Monday, with gusts near gale force before easing.
- Banks Peninsula: 5-10pm Monday, when strong southwesterlies may approach severe gale.
MetService says there is a moderate-to-high chance of some of these watches being upgraded to full warnings, as the system intensifies.
Heavy snow to blanket alpine highways
Several key South Island alpine passes are expected to see heavy snow during the storm, prompting MetService Road Snowfall Warnings:
- Milford Road (SH94): From 11pm Sunday to 3pm Monday, 20-30cm of snow could accumulate near the Homer Tunnel, with lighter flurries down to 500m.
- Lindis Pass (SH8): From 10am to 10pm Monday, 10-15cm could fall above 700m, with lighter amounts to 300m.
- Arthurs Pass (SH73): From 4pm Monday to 3am Tuesday, 15-25cm (possibly more) could settle above 700m.
- Porters Pass (SH73): Over the same period - 4pm Monday to 3am Tuesday - 10-20cm of snow could accumulate at higher elevations.
Authorities are urging motorists to carry chains, delay travel if possible and check the NZTA road updates, before driving through alpine routes.
'Stay up to date'
"Warnings and watches are now in force," MetService said. "People are advised to keep up to date with the latest warnings."
Forecasters warn that the system's intensity could still increase, and that further warnings and watches are likely to be issued later Sunday and early Monday.
The storm is expected to move east of the country by Tuesday afternoon, but lingering travel disruption and clean-up work could continue into midweek.
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