Megastorms Could Drown Massive Portions of California: Scientific American
An alarmist title, but the article is interesting.
More on Atmospheric Rivers here at NOAA
Even without any change to weather or climate as a result of human action, the traditional [normal] weather patterns are bound to cause more destruction as we build more structures, and build in more places. It's just pure plain math. If a flood course down a river towards a community of 10,000 people, it will cause more damage than a river flooding down towards a community of 100 people. And it takes much more time to move those 10,000 people out of the way of danger.