As Auckland copes with unprecedented flooding, Mairi Jay points to lessons from extreme weather events in British Columbia that could be vitally important for policy-makers and administrators here

“Expect extreme weather events” the climate scientists tell us. But sometimes the extreme is beyond our imagining. On Thursday January 26, New Zealand’s Met Service predicted heavy rain for Northland, Auckland, the Coromandel and Bay of Plenty and warned of road slips and traffic chaos. The following day, Auckland experienced more than its monthly average rainfall for January in 24 hours, leading to widespread flooding and devastation. It was Auckland’s wettest day on record, while January was the wettest month. Niwa weather described it as at least a one-in-200-year event. So how to prepare for the unimaginable?

One way is by learning from the responses of unimaginable events elsewhere.

An example is the series of weather events suffered by residents of British Columbia, Canada in 2021, in which unprecedented heat, fire and floods overwhelmed large parts of society. British Columbia shares many similarities with New Zealand. The population of 5.3 million is only a few thousand more than New Zealand; the land is mountainous, with limited areas of agriculture; the climate varies between mild near the coast and more extreme inland, and the economy is heavily dependent on primary production and extractive industries. Vancouver, the main city and Canada’s largest port, is connected by a thin line of road and rail through the Fraser River valley to the rest of Canada. The events of the summer and autumn of 2021 could equally happen in New Zealand

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In late June, 2021, a high pressure heat wave developed over the west coast of Canada and the USA. It became trapped by low pressure systems east and west and formed a heat dome over a wide area of inland British Columbia. On June 29, the little town of Lytton registered the highest ever recorded temperature in Canada at 49.6C. Wildfires broke out all over the province (and neighbouring states of Washington and Oregon), some reaching hundreds of square kilometres in area. The next day, wildfire destroyed 90 percent of Lytton. Over the several weeks of the heat dome, crops and orchards were scorched, roads were damaged as asphalt melted, rail operations were seriously disrupted, businesses had to close because of the heat, workers were laid off and suffered income loss, and more than 600 people died of heat exhaustion. The fires destroyed hundreds and thousands of acres of forest and displaced almost 33,000 people.

Autumn brought rain to a severely scarred land. The effect of the Autumn rains were made worse by steep hillsides bare of vegetation, and soils that had lost their capacity to absorb moisture. Landslips and floods caused damage and disruption to homes, communities and businesses, roads, bridges, culverts and flood protection works were breached or destroyed and there was more loss of crops and orchards. The rich agricultural lands of the lower Vancouver mainland were submerged under metres of water. Vancouver and its port were cut off from the rest of Canada, causing supply chain disruptions that affected the nation as a whole.

Research into the impacts of the heat wave by the British Columbia coroner’s office offer important lessons for Auckland and New Zealand.

According to the report:

* 98 percent of the deaths happened inside peoples’ home, not outside; most Canadian houses have been built to keep heat in and the cold out;

* 67 percent of those who died were 70 or older, and many had a chronic health condition;

* 56 percent of victims lived alone;

* Most of the victims lacked access to cooler buildings or air-conditioned spaces;

* Most of those who died “lived in socially or materially deprived neighbourhoods”;

* A slow response from agencies tasked with notifying the public about the dangers of extreme heat;

* Response agencies were overwhelmed by the number of calls and were slow to respond to distress calls and ambulance and emergency crews were ill-equipped to handle the flood of calls they received;

* The media failed to make clear the seriousness of the situation, for example using images of people playing in swimming pools or enjoying a cold drink instead of showing the dangers of heatstroke. Lack of appropriate warning images meant that many people/organisations failed to realise the severity of the situation and consider possible effects on vulnerable neighbours;

It’s likely that many of those points would apply equally to Auckland and New Zealand. Most of our housing has been built to keep the cold out and the heat in. Many people on low incomes or in rental accommodation live without heat pumps, or the income to afford the cost of electricity or a trip to a swimming pool. Many live alone. Our media tends to ignore the dangers of heat for the old, the poor or people with medical conditions, preferring to put a positive spin on summer heat.

As a follow-up to the heat wave, the British Columbia chief medical officer has called for special observation and assistance for vulnerable communities and vulnerable groups, and a better public messaging and alert system to help the public better understand the risks of extreme heat.

In short, the lessons from the British Columbia heat dome are vitally important for policy-makers and administrators here.

Lessons from the British Columbia floods are very much the same ones we already know and aim to act upon in New Zealand, although the follow-up takes time:

* Stop building on floodplains;

* Design roads, rail, bridges, culverts, stopbanks and other infrastructure for 1000-year flood levels, rather than 100-year floods.

* Restore natural ponding systems such as wetlands and swales;

* Allow space for rivers and streams to overflow and meander;

* In urban areas, find ways to allow rainfall to sink into the soil;

* Revegetate erosion-prone hillsides;

* Ensure that monitoring and forecasting systems can provide information to communities and relevant authorities in time to prepare for flooding emergencies;

* Ensure the ready availability of rescue and recovery equipment.

Perhaps policy-makers and administrators In New Zealand need to take the lessons of British Columbia’s coroner closely to heart.

Dr Mairi Jay graduated from Waikato University with a PhD in environmental planning. She practised as a professional urban and regional planner for 15 years before becoming a senior lecturer at the university.

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