Look how there are three atmospheres in the valleys inland from the Coast Mountains and the rainforests of the Pacific shore. The first one is high and wet. It’s only wet because it is at a lower pressure than the deeps down below. Notice how rain can fall from it but never reach the ground. As it touches the middle atmosphere, it is absorbed by the air, super-dried by being pushed by the spinning of the earth down into the depths of the valley. Sometimes a little of that water makes it down into the deeps, mind you.
Dramatic shadow from the sun, too!
The third atmosphere is beneath the ground, where the roots of the trees and grasses breathe. In a landscape like this, it’s more useful to talk about depth and pressure than about altitude. Water flowing down through water channels, or even through the soil, brings the climate of the hills down into the deeps through the subsoil atmosphere far more effectively than it does in the air. Intriguingly, in both the grasslands of the Okanagan and the Cariboo, there are three grassland zones, corresponding to zones of air pressure. Here’s my grandfather in the upper grassland of the Similkameen Valley in 1963.
Bruno Leipe and Pootzie, Above Cawston Creek
Photo: Hugo Redivo
Typically, upper grasslands finger out like fjords among savannahs of Douglas Fir trees. Here’s the middle grassland in Farwell Canyon, above the Chilcotin River, in the Cariboo-Chilcotin Grasslands, the last virtually pristine grassland on temperate earth…
And here’s a view from the lip of British Columbia’s largest sand dune, the Farwell Canyon Dune, formed by depressurized and repressurized Pacific Ocean air blowing up the hoodoos of the remnants of the silt bed of Glacial Lake Fraser.
Notice the sagebrush in the deeps down below. That’s the lower grassland. The trees down there are fed with runoff from the hoodoos. I bet you want to see the dune. Here you go…
Dan Dalgaard on the Farwell Dune
With a view over the Junction Bighorn Sheep Range. The California Bighorn Sheep of California were reintroduced from stock from this dune and the grasslands above it.
Now, isn’t that intriguing? Three atmospheres and three slightly-staggered climactic zones, with the highest atmosphere’s water being brought underground to the deepest, driest grassland through the lowest, underground atmosphere. What’s more, the lowest atmosphere, the underground one, crosses all three zones of both atmosphere and ecosystems. That’s what water can do in this amazing climate. And if you stay out late meditating on how to clarify your post from earlier in the day, what might you get as your reward? Ah, this little reminder that the sun powers this process…