Light and Latitude — Skip the Pity

This month’s dispatch from the Hoarfrost River Home for the Chronically Bewildered is more nuts-and-bolts than usual.  My goal is to dismantle a persistent myth about life in the far north. The myth is this: Just north of Winnipeg, (or is it Edmonton?) there lies a vast region of endless winter darkness, where legions of forlorn Canadians grope around like cave bats for months on end, fumbling with headlamps and flashlights, yearning for the return of the sun – which comes back in, oh, April or so?

If you will read all the way through this post, I think you will be surprised.  I was surprised myself, several times, as I delved into the details of daylight, twilight, and latitude.

About a week ago I went to fetch water from the margin of the shore-fast ice.  This can be a pleasant chore at this season, on the good days, because the ice is thin and the edge of it is so well-defined that a few swipes of the axe open a bucket-sized hole for dipping.   Plus, there is a thin skiff of snow on the beach, making the job even simpler, because the full pails of water can be tugged up to the barn or the house aboard a rugged plastic toboggan of the type sold in Alberta ranch-supply stores as a “calving sled.” Of course there are some days in early winter here when water hauling is all but impossible, with big waves battering the edges of shoreline ice, and miniature icebergs growling against the shallow lake-bottom.  This turns the water to a tannish gray soup worthy of the Missouri or the Mackenzie at flood stage.  But those days are the exception. We try to stockpile some clear drinking water in reserve for those storms.

As I strolled down to the shoreline with my empty pails, the sun had not yet risen but it was already full daylight by any measure. At this latitude, very close to 63 degrees North, the morning and evening twilight make up a huge and significant part of each day’s total light, all year long. And by a happy gift of solar angles, the period of twilight lasts longest in winter, when the days are shortest.  As I stood there with my sled and pails, I admired the alpenglow dawn that was already shining on the topmost rocks of the big bluff north of our place, as the first rays of sunrise struck the peak.

It was quarter to ten or so in the morning, which may seem very late for a sunrise in late November, although as I have mentioned here before, our home clocks at the Hoarfrost are skewed out of sync with astronomical reality, because we have for 15 years or so opted not to change our time settings all year long.  (Mark my words, in a decade or two changing clocks twice a year will be a thing of the past. It is just plain silly.) We are north of Saskatchewan here, at longitude 109, and we prefer to stick with our sensible neighbors down in that prairie province, who remain yearlong on Mountain Daylight or Central Standard Time (same thing, 6 hours off UTC). This does make morning light come “later” and evening light last “longer,” at least on the clock. It’s all smoke and mirrors, really, but it works for us.

The sun that was beaming on the top of the bluff, while I was still working in a pre-dawn twilight (at least officially), started my delving into the details of light and latitude.

I have often been taken aback by the glib assumptions people make about light and dark in the far north, and I often find myself trying to set people straight. A classic example was a brief interchange in Ottawa in September 2015. I was down there to do some talks and readings from my book Kinds of Winter. The cab driver and I were talking as he delivered me to a hotel for the night.  When I told him I lived east of Yellowknife, he immediately replied, in a thick Slavic accent, “Oh, way far north – so there it is dark six months, then light for six months?”  “Well, no,” I said, “I live near Yellowknife, not at the North Pole. We get a lot of light in a year, and in winter.”

And a month or so ago, down in Minnesota, a friend of my mother asked about our winter darkness: “Are you and your family into that part of the year now when it’s always dark up there?”  Her tone was all gentle pity and perplexity, as if she was politely interviewing someone from an obscure religious order, whose adherents were bound to a dreary regimen of annual winter fasting and flagellation.

“No,” I replied, “it’s never always dark where we live. For that you have to go way north of the Arctic Circle, and even up there you get a lot more daylight than most people think.  More than Minneapolis, for sure, over the course of a year.”

The key to all of this is twilight. Morning Civil Twilight begins when the sun is 6 degrees below the horizon, on its way up. If you are up early and outdoors, civil or  “useful” twilight starts when you realize you can turn your flashlight or headlamp off, and still get your chores done or see where you are walking.  At the other end of the day, evening twilight officially lasts until the sun slides more than six degrees beneath the horizon, on its way down, and you realize that it’s become too dark to be running a chainsaw, or shooting at a ptarmigan, or that you better turn the back porch light on if the kids are still out there playing catch (do kids still play catch in the backyard? I gather I’m showing some ignorance here.)

The principle is somewhat (but not precisely) akin to that first dawn sunlight hitting the high spots and peaks, while the valleys are still in shade.  One of my favorite phrases, coined by an author writing about a long-ago canoe trip down the Mackenzie River, is “the North is an immense mountain laid out flat.”   The result of this, with the shallower angles of the sun’s path through the skies at higher latitudes, is that in the North the day’s two periods of twilight become a significant portion of each day’s usable light.

Take it to the extremes and this concept becomes more clear. At the equator the sun rises straight up and sets straight down, plus or minus some variation. This makes twilight at tropical latitudes a very short part of each day, because the sun “moves” up or down through that 6 degrees just below the horizon in a few minutes, rising or setting. I have never been to the equator, or even close to it, but someday I would like to visit there, if only to experience that amazingly abrupt change from day to night, and night to day.

At the other extreme, the two Poles, the sun never gets very far above the horizon, but, simplified a little for the sake of this discussion, it rises on the spring equinox, stays up for about six months, circling endlessly around the horizon in various arcs, and then, at the autumn equinox, sets for six months – just as my friend the Ottawa cab driver thought it did in Yellowknife.

But. (There’s always a “but.”) The poles do get more daily light than the equator, but there is no tidy straight-line increase. In fact, the maximum annual allotment of daylight (sunlight plus useful twilight) turns out to be at 69 degrees latitude.  That is the latitude of the northernmost points of the North American and European continents, i.e. around Barrow, Alaska and Tromsø, Norway. The middle high latitudes, from, say, the high fifties to the mid-seventies, maximize the total illumination, the sum of daylight and usable twilight. At the latitude of the northernmost mainland in Europe, Asia, and North America, the sweet spot is reached, and the yield, at 69 degrees North, is the highest average daily total illumination over the course of an entire year – a whopping 15.1 hours of illumination per day.  This is direct sunlight, i.e. sunrise to sunset, plus civil twilight added onto each end of that.

At this most illuminated latitude, 69 degrees, there is one pesky detail, and it is one that I think I would find extremely hard to endure, year after year.  At 69 degrees North the sun does not rise at all between the first of December and the tenth of January.  Still, on Winter Solstice at that latitude, there are just under five hours of useful (Civil) twilight.  But no sunshine for almost 7 weeks, only twilight.  That’s a stretch.

Moving south from there in search of the really sweet spot, where the sun will always rise and set and stay up for some hours of every day of the year, while still trying to  maximize the total hours of sunlight per year, we get to – well, we get to the low 60’s of latitude, or about the latitude of Yellowknife, Anchorage, Reykjavik and Oslo. And on the flip side of winter, thanks to our friend Civil Twilight, even though the sun sets here on every night of the year, there are still six straight weeks of 24-hour daylight in late spring and the first month of summer.

If your eyes haven’t glazed over yet – as my dear family’s eyes did about three days ago when I got truly fired up with writing (and talking) about all of this – I commend you.  Just read on a few more minutes, because there is one more crowning detail, a gift for those of us in the Northern Hemisphere.

It is this: the northern and southern hemispheres are not mirror images of each other when it comes to illumination, even at precisely the same latitudes north and south.   The northern hemisphere gets more light per year. The explanation of this discrepancy did at first sort of lose me, just as parts of my Astronomy course at college once did, but this daylight difference between the hemispheres has to do with the speed and shape of the earth’s orbit around our dear old star.

All of this, from twilight to latitude to hemisphere to annual averages, is very clearly explained and well illustrated by Brian Brettschneider, an Alaskan climatologist, here:

https://us-climate.blogspot.com/2015/06/daylight-and-twilight.html

Alas, the persistent folklore of a purgatory of winter darkness, lying just north of a 50-something mid-latitude, will be hard to dispel. It appeals to people’s perverse and well-entrenched fascination with Misery and the Far North. Authors and poets milk the drama of this, even those who really should know better.  Here is a character from Rudy Wiebe’s widely acclaimed historical novel A Discovery of Strangers, describing the onset of winter for Franklin’s overland expedition in 1820-21, near the present-day location of the village of Wekweeti:

“And the sun did lie lower and lower on the horizon until it disappeared altogether and we lived in an endless darkness for over a month, relieved only by stars and moon and the aurora, or firelight.”

Hold on here. The location of Fort Enterprise, as Franklin called the site, at 64⁰ 28’  North (X 113⁰  06’ West), would have had, and still does have, on the very shortest day of the year, no less than three hours and 55 minutes of direct sunlight, plus two hours and 50 minutes of useful morning and evening twilight, boosting total daylight time to 6 hours and 40 minutes on the winter solstice.  “An endless darkness for over a month” simply does not happen there. Never has, at least since the Earth adopted its present orientation in space. The myth persists. As in so much writing about the far north, it seems to be too hard to resist a little exaggeration. Hyperbole makes for dramatic images, and it may help everybody down in Ottawa, Toronto, Minneapolis, and Chicago feel better about their long dark winter nights.

Six p.m. as I proofread this. Twilight has faded away.  Today, the last of November, we’ve had our 5.63 hours of sunlight, and our 2.12 hours of twilight, and Ottawa has had its 9.03 and 1.11; Chicago its 9.37 and 1.03. Over the course of the year, the average total daily illumination in the three places is: Hoarfrost River: 14 hours, 45 minutes;  Ottawa: 13 hours, 20 minutes;  Chicago: 13 hours, 12 minutes.

It will be dark tonight for many hours, up here and down there.  There are many weeks of this ahead.  We will all be glad when once again the swing of solstice passes and we start to gain a few minutes of daylight again.

Perhaps I have written all of this just to cheer myself up. And if so, it seems to be working.  Have a nice night, wherever this finds you.

Footnote: If you want to generate a printable year-long table giving times of every day’s sunrise, sunset, twilight, local noon, plus total and average daylight, for your precise location, all courtesy of the National Research Council of Canada, go to:

https://www.nrc-cnrc.gc.ca/eng/services/sunrise/advanced.html

If you run into problems with that, drop me a line.  This is one of the few things I know how to do on the confuser and the inter-web. I enjoy it, and I can help if you need it.  daveolesen@gmail.com