Fall Fog Fest

You might call it Indian summer and love it, or you might lament that this marvellous stretch of weather we’re having comes when most of us are heading back to school and to work. Too bad we can revel in it only on weekends, whereas Monday to Friday doesn’t leave much time. And worse still, the special foggy piece that comes along with the weather is very easy to miss. This fleeting phenomenon, like so many of the great things happening in our parks, is best seen in the early morning.

Our weather forecasters certainly love this weather. It’s their time of the year to get the forecasts bang-on correct. They deserve it. Let’s face it, being a meteorologist here on the West Coast can’t be much fun for most of the year. No fronts sweeping in off the Pacific, just day after day of ‘sunny tomorrow, and the day after, and…’ . An end-of-summer high pressure system has settled over the Coast, and is bringing us cool nights, warm days, and day-long blue skies and sunshine. However, just as the sun breaks over the horizon in the morning, our parks are magically transformed by fog.

With clear skies overnight, the ground radiates its daytime heat right back into space – no clouds to provide a warming ‘blanket.’ The result: the air closest to the ground is cooler than the air immediately above it, and the moisture in that cooler air condenses forming minute droplets – fog, technically speaking, radiation fog.

You can see it at Deer Lake,

and Burnaby Lake,

but only briefly. The sun rapidly burns off nature’s transformer, and we’re back to clear landscapes, and no hint of what was there minutes before.

Not only does this fog fest depend on where you stand (low areas are best), but interestingly it depends too on where you look in relation to the sun. If you look toward the sun, much of the light is dispersed through the airborne water droplets making the fog visible,

but when you look at a more oblique angle, the fog just about disappears.

The two pictures above of the foggy doggy walker were taken less than 30 seconds apart. The fog really didn’t change in that time, but my angle in relation to the sun did.

So check it out. Take a few minutes if you can on your way to work or school to take a look. Right now the best time is right around sunrise, and the event is pretty well over in an hour. If you’re late for work, say I said it’s OK. Sorry, but I can’t give permission to be late for school. You’re on your own for that one!