Hi Cynthia. You're right, that article seems to be focusing on LA, perhaps lobbying for flood control in the LA area. A sustained Atmospheric River event would affect more than the Whittier Narrows Dam.
The event they briefly refer to was a crazy event that extended from California through Oregon and on up to Washington. Much of the Central Valley in California was under water, and there is really nothing that can be done about that if it happens again. The drainage of immense amounts of water over hundreds of square miles can't be significantly improved, it would simply be a mess. Here's a Wiki link. Click on the map near the bottom of the article to get an idea of how much land would be covered with water.
https://en.wikipedia.org/wiki/Great_Flood_of_1862There's also concern that something similar may occur in the Netherlands. The drainage there would simply be too slow to effectively deal with the amount of water that could be deposited, and the dikes would end up keeping water in instead of keeping it out...
Of course, there are a bazillion things that can and eventually will come to pass that are horrible, but since we don't know when, we just don't worry about them. While Kilauea was erupting, an article from UC Berkeley about the potential danger from the Hilina Slump came to light. It is an event that only happens every hundred thousand years or so, but each time it does, it's got to be absolutely insane...
http://seismo.berkeley.edu/blog/2018/05 ... slump.htmlAt the end of the article, they mention almost casually, "The huge slide could generate a magnitude 9 quake, which is comparable to the largest earthquakes ever measured. It would also generate a megatsunami with an estimated wave height of more than 1000 feet throughout the islands. Geologic records show that about 110,000 years ago, long before any of the adventurous Polynesian seafarers had reached the island chain, Hawaii was rocked by such a slump and engulfed in the resulting huge tsunami." A 1000 foot tsunami with close to zero warning time...just about everyone in Hawaii would be killed...but since we can't predict it, why worry? Sometimes, that seems a little crazy to me. But I don't see any good options, so I will quite happily vacation in Hawaii anytime I can.
z