Wednesday, November 12, 2008

Rivers in the Sky

I've been reading about atmospheric rivers. These are enormous channels of moisture-laden air picked up in the mid-latitudes, concentrated into the channels by cold fronts, and transported by strong winds towards the poles. Occasionally a river is formed from water picked up in the tropics. The tropics, as we know, has lots of water. These tropical atmospheric rivers get pushed ahead of tropical storms, which are also heading out at high speeds. One such tropical river begins around Hawai'i and flows in a northwesterly direction towards North America, where it bumps into mountains. The mountains divert the flow upwards. Up air is cooler than down air, so as this river in the air flows up the mountains the moisture condenses and flows back down as rain.

Which explains why the sky has become a river, flowing down from the heavens in a steady stream and flooding the earth.

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