Mountains make a barrier for moving air. The wind pushes air, and clouds in the air, up the mountain slopes. The atmosphere is cooler at high elevations, and there is less of it: lower pressure makes it hard for lowland animals to get enough air to breathe. Dense masses of warm, moist air that move up and over a mountain swell as the air pressure confining them drops away. The air becomes colder in the same way as a pressurized spray can's contents become colder when the can's pressure drops rapidly. (The phrase that describes this phenomenon is adiabatic expansion.) Water that existed as a gas under the high pressure and temperature of the flatlands now condenses into cool droplets, and clouds form over the mountain. As the cloud continues to rise, droplets grow and grow, eventually becoming too heavy to float in the air. The clouds dump rain, and snow, on the mountain slopes. After topping the crest, however, the clouds may have no more moisture to rain on the other side of the mountain, which becomes arid. This rain shadow is best illustrated in the Sierra Nevada mountains of California, where the tall Redwood Forests cover the ocean-facing side of the mountains and Death Valley lies in the rain shadow.from Mountains - Weather Effects Of Mountains
I first thought this whole weather thing would be a problem and make hanging clothes on the line a bit tricky. Then I realized that the neighbors didn't seem to care what the weather was--they just hung clothes out whenever they were moved. So the conclusions I found were these:
- If I look out all the windows and see even a small patch of blue anywhere, the clothes should eventually get dry today.
- The rain is so fine on this side of the mountain that it doesn't hinder the drying process to any degree unless it's blowing sideways. [Sometimes, it's pleasantly balmy and I don't realize it's actually raining (misting, we used to call it) until I get outside.]
- Except for the dreaded winter months, the rain is always intermittent--the blue skies and sunshine can break through the clouds 10 times over a period of a few hours, interrupted by some mist or drizzle or having both sunshine and rain simultaneously.
- Even if the clothes don't get dry today, they will be nicely rinsed in pure, mountain rainwater and will dry tomorrow.
I have learned not to worry about the laundry. And I have, thus, learned not to worry about many things over which I have no control. Life is always a learning process.