Okay, this is what I think. That's a bunch of BS about the rainfall and all. I know the true signifance of the Continental Divide and it has nothing to do with rain, water flowing here or there, or anything like that.
Look at the photos of Zip. When Zip is on the east side of the Continental Divide, he's almost normal.
When Zip is on the west side, he's totally out of it!
Photos don't lie! Case closed!