Why extreme cold thresholds are different across Nunavut and the country

One region’s nice day is another’s frigid forecast

Etuangat Akeeagok built a snow jump outside his hometown of Grise Fiord in 2016. Grise Fiord, along with the rest of central and western Nunavut, has the highest extreme cold threshold in the country. (File photo)

By Emma Tranter

For Nunavummiut, a temperature of -30 C could be considered a nice January day.

But for people living 2,300 kilometres south, in the Greater Toronto area, that kind of chill warrants an extreme cold weather warning from Environment and Climate Change Canada.

So how exactly is “extreme cold” determined, and why is the threshold for declaring it different across the country?

In Nunavut, the threshold to issue an extreme cold warning is the highest in the country, according to Environment and Climate Change Canada meteorologist Sara Hoffman.

Baffin Island has an extreme cold threshold of -50 C or a windchill index of -50 C. In Iqaluit, that temperature means local elementary schools close for the day, as happened one afternoon last week.

But for the rest of Nunavut, that threshold is slightly higher at -55 C. That temperature must also persist for at least two hours for a warning to be issued.

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For example, a temperature of -50 C in Iqaluit warrants an extreme cold warning, while the same temperature in Baker Lake does not.

So why the five-degree difference?

Hoffman says Environment Canada takes into account a number of factors, including how frequently a region experiences cold temperatures and what effect those temperatures have on people who live there.

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“Usually we have consultation with territorial and provincial health authorities to help come up with that number,” she says.

Regions like southern Ontario, which have an extreme cold threshold of -30 C for at least two hours, experience that kind of cold less frequently than places like Baffin Island.

In fact, southern Ontario has one of the lowest extreme cold thresholds in the country.

“Sometimes health authorities will even look at emergency room visits or how that temperature will impact the body physiologically with their own threshold,” says Hoffman.

“In the south we have a higher population density and also a more robust reporting structure for those types of things. So we can look at that type of data to help in that analysis and create that type of threshold.”

In the North, the focus is more on the climate, rather than things like visits to the hospital, as that can be more difficult to measure, Hoffman says.

“There has to be special consideration for the North, given there’s a bit less of a robust network that way. There is special consideration given to that when we set those extreme cold warning thresholds. And that’s why the thresholds are always set in partnership with provincial and territorial health authorities.”

Climate change is causing the Arctic to warm at a faster rate than the rest of the country. But how does a changing climate factor into the extreme cold threshold?

“As for extreme cold thresholds changing due to climate change, climate change has not changed extreme cold thresholds up until now. It is possible that in the future it could. However, we expect more extreme swings in temperature and weather as our climate changes, which would mean a change in the alerting criteria would not be warranted,” Hoffman says.

Although Nunavut is consistently cold, it doesn’t crack the top five for the number of consecutive days where an extreme cold warning was in effect in 2018- 19.

The top five coldest places in Canada for the most consecutive days according to Environment and Climate Change Canada (with the extreme cold thresholds in brackets) are:

1. Tadoule Lake, MB—44 days (-45)
2. Fond-du-Lac—Stony Rapids, SK—41 days (-45)
3. Tie with 40 days: Brochet, MB, and Wollaston—Collins Bay, SK (-45)
4. Fort Chipewyan—Wood Buffalo National Park, AB—39 days (-40)

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(5) Comments:

  1. Posted by INUK on

    I keep reading and hearing about global warming . I DON T FEEL IT !!

    • Posted by Unequivocal Evidence on

      It’s GLOBAL warming (or, Climate Change), not, don’t you feel warmer in your tiny fraction of the world? Either way, the climate is changing. Here’s the evidence:

    • Posted by Dont feel it on

      Don’t be ignorant, nobody “Feels” global warming. Look at the stats. Extreme weather events are happening more frequently, ocean levels are rising, glaciers are melting, average temperatures are slowly rising too. Look at the average temps 50 years, 20 years ago, 10 years ago… Go to Tuk, their shoreline is eroding by up to 30 feet per year. THIRTY FEET.

      • Posted by Jim MacDonald on

        Look back to July 15, 1942. The “Lost Squadron” had to make an emergency landing onto Greenland’s ice because of thick cloud cover and low fuel. In 1992, fifty years later, one P-38 was removed from the ice and restored. To get to the aircraft, thick ice melted and chop down 250-300 feet.
        Sea level’s rising? Where is this melt coming from? Antarctica locked into deep cold year round. Tiny summer melt, if any. Arctic sea ice melts, but never rise the seas or Hall Beach and Arviat would disappear each summer under water. Tuk, as said, natural soil eroding.
        Greenland glaciers hanging steady. Calving in summer while winter snows continue accumulating yearly. Greenland glaciers data shows some thickening and or increasing. Montana’s Glacier National Park removed signs stating the glacier would be gone by 2020. Climate Change (aka global warming) fear just didn’t happen and far from the arctic.
        Looking at NOAA‘s historical data for the US states, 23 all time record highs are from the 1930s and another 36 record highs before 1960s.
        Diving into NOAA’s hurricane data shows the strongest hurricanes to make US landfall happened before 1965 for 9 of 13. Tornadoes continue downward, less happening since 1970s.

  2. Posted by Bob on

    Great story!

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