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The Sea-to-Sky-to-Sage Highway

By Bob Brett,

Whistler Naturalists

After months of media bombardment portraying Highway 99 as "the killer highway" it’s maybe time to come to its defence. Not only is the highway fun to drive, it passes through some of the most amazing country anywhere.

British Columbia is the most ecologically diverse province in Canada and travelling Highway 99 from West Vancouver to Lillooet is proof. Where else can you travel along a dry Mediterranean coastline, through the rainforest to lush farm country, up to a subalpine mountain pass, back down into dry Ponderosa Pine forests, and finally into a semi-arid desert complete with sagebrush and rattlesnakes – all in less than four leisurely hours?

Everyone in the country makes fun of the Wet Coast and assumes B.C. is Canada’s answer to the Amazonian rainforest. The truth is that there’s a huge gradient of rainfall which combines proximity to the ocean and elevation. Pacific storms moving onshore hit mountain range after mountain range, and each time there’s a little less juice in the clouds. But the same elevational pattern holds – mountains are always wetter than the valleys because when air rises, it cools. Colder air can’t hold as much moisture, so it falls as rain or snow. Highway 99 is a great place to see a cross-section of the different climates that result from these patterns.

The West Vancouver portion is the driest part of Highway 99 because it’s near sea level and just off the track of many of the storms pushed into the North Shore Mountains. This narrow band of sun-baked coastline resembles the Mediterranean, and not just in its climate. It is also home to arbutus, the same graceful, red-barked trees you can see clinging to cliffs here and along the Mediterranean coast.

Driving towards Squamish you move into increasingly wetter terrain. The arbutus drops out, and the trees and shrubs get bigger and greener. It’s not nearly as wet as the Clayoquot Sound rainforest (where there’s up to 5,000 mm of precipitation), but it’s a good local substitute. As you move from sea level to Whistler, a climb of 670 metres (2,200 feet), there’s less bigleaf maple and salal, and lots more amabilis fir and falsebox.

Compared to Whistler, Pemberton might as well be Dry Gulch. But from a farming perspective, there’s plenty of water with green fields and big trees to show for it. Pemberton Valley gets less rain and more sun than Whistler because it’s lower (by over 400 metres) and because much of the precipitation has already dumped on lucky Whistler.

Climb the switchbacks on the Duffey Lake Road and you’ll see Douglas-firs quickly giving way to western hemlocks and redcedars. By the time you drive past the Joffre Lakes parking lot, you’re well into the subalpine zone with its Engelmann spruces and subalpine firs. Checking last week, there was still snow in an avalanche track beside the road.