Caught Between a Tide and a Cool Place

It sounds like we left coasters are real wimps. At least when it comes to heatwaves we're treated differently than other Canadians. Environment Canada has introduced a new scale for heat warnings based, in part, on where you live.

Those of us in Lotus Land, coastal British Columbians, get the heat danger warning at 29 degrees Celsius. Other parts of the country don't get that warning until the forecast temperature is much higher.

What was once a single threshold for nearly everywhere across the country now differs from region to region, about 20 in all, with criteria that considers duration, nighttime lows and local health impacts. 

The new system has been rolled out slowly, but its purpose is urgent: to warn people as early as possible that heat can kill and is on its way.

...Even before the change from Environment Canada, B.C.'s Lower Mainland had its own threshold for heat warnings, designed after a deadly heat wave in 2009. 

Over seven days that summer, the normally balmy South Coast had temperatures that reached 40 C in areas and stayed higher for longer than authorities thought possible there. 

That week, 110 more people died than would be seen in an average summer week in the region, according to a 2012 study by the B.C. Centre for Disease Control.

110 in one week. That's something.

When I moved to the coast from Ottawa about forty years ago I loved the gentle climate. Mild summers. Mild winters. Wet, to be sure, but that seemed a fair price to pay.

It was about three years after moving west that I went to visit my family in southern Ontario at the height of summer. As I walked down the steps from that DC-9, I was struck by the blast of heat. For a second I thought I must be walking through the exhaust of the idling jet engine. No, the engine was the other way. I was just getting a blast of Ontario summer. Damn near melted. I made sure not to get too far from A/C for too long while I was there. I just about kissed the ground when I landed back in Vancouver.

A year or two after that it was back to Ontario for Christmas with the family. When I lived in Ottawa I had picked up this RCMP winter parka that had served me well in the worst of an Ottawa winter. Naturally I brought that along, figuring I had it made. Wrong again. As I walked from the aircraft to the Ottawa terminal I discovered what had protected me in the past wasn't protecting me now.

After the summer experience followed by the winter experience I realized I was no longer acclimated to Ontario weather. I couldn't bear the heat. I couldn't stand the cold. Apparently that's not perception. It's real.

Now, with the exceptions of Quebec and Nunavut, heat warnings are issued when the high temperatures are expected to last two days — rather than an hour — and the threshold varies not just by province but zones within a province. 

In Ontario, which piloted the new system in 2015, three different thresholds apply; Alberta, Manitoba and Saskatchewan have two zones; and there's just one for Newfoundland and Labrador. 

B.C., with its mountains and sea, has four — ranging from 28 C on the North Coast to 35 C in the Fraser Valley and Southern Interior. 

That's partly based on the highest five per cent of temperatures a region is likely to see, said MacDonald. 

But it's also based on health data — because if you're not used to heat, it truly is more dangerous, said Kathleen McLean, an environmental health scientist with the B.C. Centre for Disease Control, which worked with Environment Canada on the new criteria in B.C. 

"People definitely become physiologically adapted to the temperatures in the place that they live in," said McLean.

We're currently under a heat advisory with temperatures expected to reach the high 20s, perhaps even 30 C this weekend, before dropping back down to the low 20s. I don't have air conditioning and I still sleep under a down duvet at night.

I'm about a block from the sea, close enough that it gets comfortably cool overnight. I use blinds to shutter the house during the heat of afternoon. Once the sun is down and the evening cooling begins the blinds are up, those huge casement windows swing wide open and the ceiling fans team up with the breezes to flush the accumulated heat out of the house overnight.

I'm lucky. My house is situated atop a rocky escarpment that juts out into the sea.  Cooling from three sides and there's usually an evening breeze coming from one of those directions. Yet there's no guarantee this is going to last. The climate is changing rather quickly. Extreme weather events, including heatwaves, are increasing in frequency, intensity and duration.

If we're having these problems try to imagine living in Central America and other countries in that latitude where, if the theory of Climate Departure pans out, may become unlivable if only seasonally at first. The projected start of climate departure is just two to five years away so we won't have long to wait before we see what effects it has on the populace of these countries.