Vancouver, Canada’s “Cloud City”

Last week an incredible veil of heavy fog blanketed the Lower Mainland and the City of Vancouver. It got the photographers snapping some incredible pictures and the newspapers soliciting them for those pictures like the ones posted on this site by thumper.

Vancouver and the Lower Mainland of British Columbia is no stranger to fog and morning mists, particularly this time of the year. But this last foggy phenomenon was just a little out of the ordinary in its persistence and generated a lot of buzz in the blogosphere and internet chats as a result.

There followed a whole lot of buzz last week when a close relative of the photo above (but not the same; you can see it in the clouds)--the top photo of a Vancouver sunrise in the clouds-- started appearing in email boxes and blogs across the city and worldwide eventually. The other photo eventually appeared in the Vancouver Sun last Thursday and was attributed to Scott Miller. Others attributed it to photographer Blair Kent. Obviously, a number of people took photographs from that same perspective. I don’t know who took this particular one, but it’s beautiful, as are the others I’ve posted below (sent to me by a friend and unattributed). If you are one of the photographers, please let me know and I would be happy to credit you. I’d be delighted to take you on board Vinnie and interrog—uh… interview you, even!

Fog is basically a cloud on the ground, only the processes that form it are different. Clouds form when rising warm air cools from expansion. Like clouds, fog is made up of condensed water droplets which form when the air near the ground is cooled to a point (the dewpoint, actually) where it can no longer hold all of the water vapor it contains. Fog forms when rain cools and moistens the air near the ground. Infrared cooling can also occur when a cloud-free humid air mass at night creates what’s called “radiation fog”. This is most common in the fall, when the night gets longer and land and water surfaces that have warmed up during the summer are still evaporating a lot of water into the atmosphere.

Fog can form suddenly, and can dissipate just as rapidly, depending what side of the dew point the temperature is on. This phenomenon is known as flash fog. Steam fog, also called evaporation fog, is the most localized form and is created by cold air passing over much warmer water or moist land. It often causes freezing fog, or sometimes hoar frost.

Vancouver is nestled on the coast, surrounded by mountains. This makes it a prime candidate for Valley Fog, which forms in mountain valleys, often during winter. It results from a temperature inversion caused by heavier cold air settling into a valley, with warmer air passing over the mountains above. It is essentially radiation fog confined by local topography, and can last for several days in calm conditions.

What caused the spectacular fog phenomenon in Vancouver last week was either a warm moist air mass blowing over the cold snow and ice covered water and land of Vancouver, called “advection fog”, or more of Vancouver’s typical valley fog. Hard to tell. It was pretty cold but we had a spate of warmer weather too.

Fog and mist provide a photographer’s dream for strange and wonderful lighting. Fog shadows are the coolest phenomenon, as the spectacular photo below by Mila Zinkova of Golden Gate Park demonstrates. The thin fog is just dense enough to be illuminated by the light that passes through the gaps in a structure or in a tree. The path of an object shadow through the "fog" therefore appears darkened. In a sense, these shadow lanes are similar to crepuscular rays, which are caused by cloud shadows, but here, they are caused by the shadows of solid objects. Crepuscular rays, in atmospheric optics are rays of sunlight that appear to radiate from a single point in the sky. These rays, which stream through gaps in clouds or between other objects, are columns of sunlit air separated by darker cloud-shadowed regions. The name comes from their frequent occurrences during crepuscular hours (those around dawn and dusk), when the contrasts between light and dark are the most obvious.

Nina Munteanu is an ecologist and internationally published author of novels, short stories and essays. She coaches writers and teaches writing at George Brown College and the University of Toronto. For more about Nina’s coaching & workshops visit www.ninamunteanu.me. Visit www.ninamunteanu.ca for more about her writing.