|When Chinooks reach Alberta (Canadian Public Domain)|
Albertans are very familiar with Chinook winds. Other Western Canadians, like myself, born and raised in Saskatchewan, are also aware of such winds, having experienced them in some form or another across the prairies, just not to the same degree as what Albertans go through. Other Canadians have only heard tell of this potent Chinook--a native word meaning “snow eater”--phenomenon.
The warm, dry Chinook winds are unique. Alberta feels about 30-35 per year, concentrated the strongest in an area around Calgary (where the Bow Valley to the west acts as a gun barrel) south to Lethbridge. Hardly ever in Edmonton, much to that city’s annoyance, I’m sure. Chinooks occur in every season but are more prominent--and more welcoming for a day or two at least--in the winter, mostly in the months from November to April.
The Calgary Weekly Herald in a 1900 article wrote:
“Those who have not the warm, invigorating Chinook winds of this country, cannot well comprehend what a blessing they are. The icy clutch of winter is lessened, the earth throws off its winding sheet of snow. Humanity ventures forth to inhale the balmy spring like air. Animated nature rejoices.”
Chinooks originate as mild, moist weather systems off the British Columbia Pacific Coast. Moving onshore, the winds climb three western mountain ranges, cool down as they soar higher, then warm up rapidly as they descend on the eastern side of the mountains in Alberta, usually accompanied by a sudden wind direction towards the east-southeast, as well as an increase in speed.
|Where Alberta Chinooks hit |
(Canadian Public Domain)
In the land where its people like to brag that they can experience “all four seasons in a single day” and “if you don’t like the weather, wait ten minutes,” here’s two recorded examples in Calgary of the sudden shift in nature so prominently associated with Chinooks: On January 11, 1983, the thermometer climbed 30 degrees Celsius in just four hours; then, on February 7, 1964, it rose 51 degrees (the old Fahrenheit scale then), as the humidity fell 43 percent. Also, Claresholm, Alberta, northwest of Lethbridge, hit a high of 24 degrees Celsius one mid-February, 1992 day due to a Chinook. A few miles away, over the international border in Montana, the town of Loma (population 80) set a Chinook record in 1992 with the greatest temperature change in 24 hours by going from a frigid -48 to mild +9 Celsius.
Observant Albertans know how to read the skies throughout the winter because when the Chinooks come barreling towards them, especially on a cloudy day, the winds push the cloud cover away in a solid, even line: cloud to the east, blue sky to the west. It’s quite a spectacular sight! They call it a Chinook Arch.
What are the consequences of Chinooks?
On land: soil erosion, small plant damage, forest fires due to the dry ground and air, wood splitting and cracking, sounds carrying long distances, rivers and lakes losing ice at the rate of one inch per hour, trees bending and breaking, leaves on trees sprouting then dying off at next frost, the melting snow providing winter grazing for cattle and other livestock, and wire fences becoming electrified from the charge in the air. Cattle getting too close to the fences have been electrocuted. Also--mainly closer to the Bow Valley--the strong winds have been known to derail trains and blow empty semi-trailer trucks over.
For people: while the relief from cold temperatures is appreciated by most, others may experience headaches, earaches, joint pain, nervousness, sleeplessness, the shakes, and in some drastic cases a sharp increase in suicide rates.
|A Chinook Arch over Calgary |
(Canadian Public Domain)
I lived in Saskatchewan for the first 24 years of my life. During our many below-zero deep freezes, we would keep a constant eye and ear on TV and radio weather reports coming out of Calgary and Lethbridge. As soon as we got word of the temperatures rising there, we knew that the same weather system—a Chinook—would be coming our way within 24 hours. Then the winds would head on into North Dakota and sometimes into Manitoba before losing strength. I seem to also remember the wind speed usually dying down in Regina, followed by a day or two, or three or four of calm, mild days. Then, after that, back to a sudden and unwelcoming deep freeze. On many occasions, we would go to bed at night when it was 20 or 30 below and wake up to a balmy morning. At such times, it was not uncommon to see a foot of snow melt in one 24-hour period, especially in March when the sun was higher in the sky.
Chinooks may even behave in erratic hit-and-run tactics. Years ago, I spoke with an Air Canada pilot who lived in Calgary. He told me that Chinook winds had a rolling motion to them as they sped across the prairies. In the winter, from the cockpit, he could actually see where the Chinook winds were the strongest and where they were the weakest merely by the melting patterns spread out to the horizon, something a person wouldn’t normally catch while on the ground. Oftentimes, the high winds hampered landings and take-offs, too.
Chinooks made world news in December 10, 2015 in a National Post article here in Canada which had been featured with the headline: Leonardo DiCaprio witnesses a ‘terrifying’ sign of climate change in Calgary—a chinook. Apparently, when the actor, a staunch climate change activist, was filming “The Revenant” in southern Alberta sometime during the winter of 2014, he saw what he thought was the terrifying evidence of climate change, oh my. DiCaprio told Variety magazine in an article after his “scary” encounter:
“I’ve never experienced something so first-hand that was so dramatic. You see the fragility of nature and how easily things can be completely transformed with just a few degrees difference. It’s terrifying, and it’s what people are talking about all over the world. And it’s simply just going to get worse.
“We were in Calgary and the locals were saying, ‘this has never happened in our province ever.’ We would come and there would be eight feet of snow, and then all of a sudden a warm gust of wind could come.”
Well, I don’t know which locals DiCaprio had been talking to. Following the article, the “real” local Albertans who knew better raked him over the coals. Federal Conservative MP for Calgary Nose Hill Michelle Rempel tweeted: “I wish someone had explained to Leonardo DiCaprio what a Chinook is.” Others using the social media weren’t as kind in their opinions of DiCaprio’s knowledge of Alberta weather. In fact, many postings were downright nasty.