Power supply demand in New Zealand reached a nationwide all-time high on Monday, August 9, 2021, after a rapidly deepening low-pressure system moved east across central parts of the country, bringing heavy snow, severe gale southerlies, and frigid temperatures.
As a result, the country's national grid operator - Transpower declared a 'grid emergency at 19:00 local time (07:00 UTC) on August 9.
"Tonight we have reached an all-time high in demand on the electricity system, but unfortunately we have not had enough generation in the system to maintain it," the company said.
"Insufficient generation has been made available to meet demand and manage a secure system.
"Transpower in our capacity as managers of the power system (the System Operator) has asked the distribution companies to reduce load across the country. Different companies will do this in different ways, some manage via load control on hot water, some manage via customer disconnections. The situation is expected to resolve at 09:00 pm tonight once peak demand for electricity has passed."1
On one of the coldest nights of the year, cities and towns across the North Island were plunged into darkness, Stuff reported, adding that this was the first time in 10 years that such an emergency has happened.2
Power distribution companies managed to increase available power by 5% by 20:20 LT and resolve supply shortages by 21:00, their report added.
While the total number of affected customers remains unclear, reports mention up to 20 000 homes were left without 'heating after high winds brought down power lines and cold weather saw power use surge beyond generation capacity.'3
Cloud free across Canterbury in this image, so all that white is snow! Even lingering on to the plains about Methven, although much of that should melt in the sun this morning. Hard to spot under the cloud over Otago and Southland, though. Credit: JMA/Himawari-8, Met Service
"The low dragged up cold air all the way from Antarctica," said MetService Meteorologist Stephen Glassey.4 "Snow has been falling in parts of both the North and South Islands, affecting many roads."
Temperatures in most parts of Auckland dropped to 5 °C (41 °F) at 21:00 LT on August 9, with the coldest in Ardmore at 3.3 °C (37.9 °F). Hamilton hit 0 °C (32 °F) at 22:00 LT.
Capital Wellington dropped to 5 °C (41 °F) by 17:00 LT and to 2.6 °C (36.6 °F) at 18:00 in Lower Hutt.
On the morning of August 10, Hanmer Forest was at -5.7 °C (21.7 °F), Reefton at -4.1° C (24.6 °F), Hamilton at -3.1 °C (26.4 °F), Lake Tapo at -2.8 °C (26.9 °F), Upper Hutt at -0.5 °C (31.1 °F) and Auckland at 1.4 °C (34.5 °F).
Luckily, this event was short-lived and power outages were mostly resolved within 12 hours. This wasn't the case in Texas in February 2021 when hundreds of people died after a major polar blast brought exceptionally cold temperatures for a prolonged period of time.5, 6, 7
The storm is moving away from New Zealand on Tuesday, August 10.
Cold southwesterlies will ease today and snow showers will clear the country, leaving only a few rain showers affecting some southern and western parts of New Zealand, NZ Met Service said.
The next significant weather system is a front expected to reach South Island on Thursday, August 12, and move across the North Island on Friday, August 13.
The front, preceded by strong northwesterlies, will bring a period of rain as it moves north, with heavy falls in the west of the South Island.
"This next weather system will be completely different," Glassey said. "Instead of air coming from Antarctica, most of the air will be coming from Australia, so it will be comparatively warmer, and snow is not expected to be a factor like it is with the current weather system."
1 Transpower NZ - FB
2 National demand for electricity reaches all-time high, cities plunged into darkness to reduce load - stuff
3 Widespread power outage in the middle of winter - thousands affected - NZ Herald
6 Unprecedented Texas deep freeze results in 600 million dollar crop loss - TW
7 Texas 2021 deep freeze left nearly 200 people dead, new analysis shows - TW
Featured image credit: NIWA
Producing content you read on this website takes a lot of time, effort, and hard work. If you value what we do here, please consider becoming a supporter.