Cape Breton boasts a coat of many colours. From the bright greens and colourful wild flowers of spring, deepening into the mature greens and late bloomers of summer, and climaxing with the spectacular flaming foliage of fall. This glorious palette is set against the brilliant blues of sea and sky.
Winter has its own special beauty, featuring wind-sculpted snow drifts, lace spun from ice, and abundant patterns and textures illuminated by light and shadow. I explored this aspect of winter in Winter’s Art Gallery. But for all its icy beauty, Winter seems to specialize in monochrome, like a photographer who works in black and white, or a blue-period Picasso.
And yet there is colour in winter, all the more special because it stands out against winter’s white. So here is another wintry art gallery, this time focusing on the colours of winter, captured over the years here in the Holler. I hope these colours brighten your day as we make our way toward Spring Equinox. And remember, you can click on small pics to see them full size.
Digging the Winter Blues
Winter days are not always grey, and on sunny days those blues really pop when contrasted with bright snow white. What makes that sky so blue?
The short answer is Rayleigh scattering. We know that visible (white) light is composed of a spectrum of colours, displayed in rainbows and light refracted (bent) by a prism. Light has wave-like properties, and the red end of the spectrum has longer wavelengths while the blue and violet light have the shortest wavelengths. As yellow-white sunlight enters our atmosphere it interacts with air molecules and the waves are scattered. Short wavelengths are scattered the most and thus give the sky its blue colour. (Violet is the shortest wavelength, but there is more blue in sunlight and our eyes are more sensitive to blue.) At sunrise and and sunset, the light travels through more atmosphere. The blue light is scattered away, leaving the longer wavelength reds and oranges to delight our eyes.
Why is the Ocean Blue?
Of course water reflects light like a mirror, as in this photo from Dogs and Drift Ice. But water also filters sunlight. Water molecules absorb more long-wavelength reds and oranges and leave behind the shorter-wavelength blues and blue-greens. So while a glass of water appears colourless, water does have a blue hue that we can see when looking into deep bodies of water like the ocean. Divers observe this blue light because it penetrates deeper into the water than long-wavelength red light.
Winter’s Pond Art
I feel very lucky to live above a pond that offers something for every season. I’ve written about L’il pond and its various inhabitants a number of times, but winter is a surprisingly dynamic season for this little body of water. It goes something like this: Ice forms on the surface as temperatures drop. Snow blankets the ice. Under the ice, just as in summer, (see Ups and Downs in the Holler) water continues to drain out through the permeable soil. As water levels drop the ice eventually collapses under its own weight, sometimes cracking like a rifle shot, other times slumping with a whump.
But of course, this being Cape Breton, sooner or later everything changes. It rains buckets. Or we get a warm spell and a big snowmelt. Or both. Rain water and snowmelt from the highlands pour into the pond, raising the water level. Some ice may be frozen to the ground, but most of the ice surface will be lifted by the rising water. This is one of the miracles of water – most matter is denser in solid form, but ice is less dense than liquid water and thus floats, enabling aquatic life to survive winter’s deep freeze.
So the ice rises along with the rising water, but the ice surface is now smaller than the expanding pond perimeter. Water flows around the edge of the ice, over grounded ice, and collects in low-lying melt-water pools. And it is in these places where water and light do their magic dance.
Over the years I have enjoyed a gorgeous array of colours. The three photos below are all of the same place, just below the yurt where I lived for eight years.
A pool like an
shining with the
nacre sheen of
Now that same
pool is an aquamarine gemstone!
And now, transformed yet again, it’s like an amulet for a giant,
carved from jade.
So if water is true blue, why does it display such a kaleidoscope of colours?
This is a multi-coloured question with a multi-faceted answer. I’m no expert on optics – you could even say I’m walking on thin ice – but here is my best shot. (As always, I welcome your comments and corrections.) Water can take on a variety of colours due to light being reflected, filtered, or scattered; by suspended particles like silt or clay; by dissolved substances like iron or copper; or by microorganisms like bacteria or algae. Or, just to keep things interesting, by some combination of the above.
Take mountain lakes, like Moraine Lake in Alberta, featured on older $20 bills. These lakes are famously turquoise from ‘glacial flour’, finely-ground rock particles suspended in the water column. The rock particles scatter light in the blue-green part of the spectrum, and some is scattered back to the surface to our appreciative eyes. So, suspended particles + light scattering = turquoise lake photo op.
Rivers can be muddy brown or reddish from suspended silt or clay (like ‘The Big Muddy’ Missouri River). If the silt or clay settles out, the water will become clear. Conversely, substances that dissolve in water give it intrinsic colour. Think of rushing rivers in spring, tawny with the dissolved tannins released by decaying organic matter. Water with high iron content may look pale yellow or rust-coloured. Dissolved copper from corroding pipes will give water a blue/green tinge.
Reflections on a Pond
When light shines on still water, some rays penetrate the water and are refracted (bent) while others are reflected back off the surface. Depending on your viewing angle, the water may act like a mirror, echoing the world above its surface. In winter these watery pond mirrors are neatly framed by ice and snow.
Why is the Water Green?
I posted the photos below on Facebook and they sparked a question: ‘Why is the water so green?’ I’d always attributed the pond’s wintry colours to light reflecting and refracting and scattering, but that question got me thinking more ‘deeply’ about that vivid green.
L’il Pond is a lively place all summer, teeming with aquatic plants, including its namesake lilies, that die off each fall. Eutrophic bodies of water like the pond are rich in nutrients, like nitrogen and phosphorous, that allow phytoplankton to thrive. Apparently some of these single-celled algae can survive all winter, feeding from that rich nutrient bath and giving off oxygen that benefits the aquatic organisms beneath the ice. These suspended microscopic algae contain chlorophyll that can give water a green colour. Decaying organic matter consumes oxygen and releases dissolved tannins that dye the water a tawny gold or sepia brown.
Like an artist mixing paint on a palette, winter blends these watercolours to achieve a rich array of hues, from earthy ochres and warm olive greens, to gem-like emeralds, peridots, and the many shades of jade.
Why is the Water Green and Blue?
I’ve ‘reflected’ on this and here’s my best guess. The green water at the top is last year’s pond water that escaped to the surface as the ice contracted. It has that rich olive-green colour from suspended and dissolved organic matter as described above. The water on the bottom is fresh from the highlands and relatively pure. It has a crisp minty-blue colour from reflected and scattered light. As the fresh water mixes with the older pond water, winter will blend yet more watercolours to enrich its paintings on the snow-white canvas.
The Colours of Ice
When water retains its colour after freezing, the colour must be due to dissolved or suspended matter that remains captured in the ice lattice. This gorgeous green ice supports the idea that those watery greens were not just a trick of the light.
Delving Deeper into the Blues
I’ve been lucky enough to see glaciers out west and icebergs off the east coast. Both glaciers and icebergs can display striking blues within the white. As with liquid water, both ice and snow filter white sunlight. The surface reflects almost all the light and is a blinding white, but as the light penetrates deeper, the long-wavelength reds are absorbed and the blue and blue-green wavelengths are scattered, some finding their way back to our eyes.
There haven’t been any glaciers in Cape Breton for about 10,000 years, and although we do get smaller ice floes, you have to hop on the ferry to Newfoundland to see the really big bergs. But dig a hole in a snowbank, or look into a crack in the ice, and you might detect a hint of blue.
Like liquid water, ice can also reflect light for subtle displays of colour, as seen here.
The Colours of Snow – the Shadow Knows (but I don’t)
Next time you’re looking at snow, take a gander at the colour of the shadows. When the sun is low in the morning sky, shadows on snow are a beautiful blue. When the sun is high overhead, they tend to fade to grey, but as the sun drops to the western horizon, the shadows stretch out and shift back to blue.
Shadows occur when light is blocked – a shadow is the absence of light. When the sun is high a shadow is the absence of white light. That should make shadows black, but often there is enough reflected light bouncing into the shadow zone that they tend to shades of grey. As I described earlier, there are more long-wavelength reds and oranges when the sun is lower in the sky. When this light is blocked, the absence of red and orange light results in a blue shadow, visible on the snow-white backdrop. I think. Maybe.
But it’s more complicated than that. I’ve seen both blue and grey shadows at different times of day. What’s going on? There are a handful of differing opinions on the cause of blue shadows on the web, but which, if any, is correct? I have my own ideas, but I’m not sure if they’re correct either. This is the kind of conundrum my science-geek buddies and I use to discuss over pints at the pub. So if any of you want to join me in puzzling over snow shadows, I’ll buy the beer.
Okay, ‘nuf of dem blues – it’s time to get in the pink. There is a lovely phenomenon known as ‘alpenglow’ when snowy mountain peaks glow rosy pink at sunrise or sunset. But pink snow can be more than just a transient reflection. Algae can lend their colour to snow as well as to water, as shown in the photo below from Dogs and Drift Ice.
Our drift ice often displays this red-pink tinge. I’d always heard the colour came from the red soils of PEI hitching a ride, but then why is the red on top of the floe? While writing that blog I learned that pink snow is caused by Chlamydomonas nivalis, a unicellular green alga that contains a red carotenoid pigment called astaxanthin. That’s a mouthful, but it goes by the wonderful moniker ‘watermelon snow’ and can also be seen in the mountains.
And just a final word of caution about the colour of snow: If it’s yellow? Don’t eat it!
More Colourful Signs of Life
Winter snows cover grass, shrubs, mosses and such with a soft white blanket. Amphibians burrow into mud. Critters go underground or even hibernate. Many of our colourful birds fly south. All those formerly brilliant leafy trees are now bared to their buff. But life goes on in winter and sometimes brings a bit colour into our lives.
Leafy trees are winter bare but here in the mixed forest there is still greenery. Conifers may lack the pizzazz of deciduous trees most of the year, but they are indeed ‘evergreen’ and wear their subdued colours all year round. Many of our aging white spruce are draped with ‘old man’s beard’, a sage-green lichen (genus Usnea). Last year’s bird’s nest is suspended high above the snow and made mostly from this lichen. This year we’ve had barely any snow, so green things normally hidden are making a rare winter appearance.
And, of course, there are still animals out and about. While many birds head south, blue jays stay and brighten our day. Most mammals wear coats of grey or brown, but there are a few more colourful characters in the neighbourhood.
It seems fitting to end this post with sunset and its spectacular colours. Back in Calgary I used to ride my bicycle to work along the Bow River bike path. I loved those mornings when the river glowed red and rose just before sunrise. Here in the Holler I marvel at the sunset colours captured by the pond and framed by white snow and ice. I’ll leave you with these final reflections on the Colours of Winter.
Sue McKay Miller
March 16, 2023
p.s. Phew! Just under the wire to get this winter blog posted before we swing into spring.
Have a Happy Spring Equinox!