An Arkstorm like in 1861-62 or worse is likely inevitable within 50 to 100 years

4. An ARkStorm is plausible, perhaps inevitable. Such storms have happened in California’s historic record (1861-62), but 1861-62 is not a freak event, not the last time the state will experience such a severe storm, and not the worst case. The geologic record shows 6 megastorms more severe than 1861-1862 in California in the last 1800 years, and there is no reason to believe similar events won’t occur again.
5. The ARkStorm is to some extent predictable. Unlike for earthquakes, we have the capability to partially predict key aspects of the geophysical phenomena that would create damages in the days before an ARkStorm strikes. Enhancing the accuracy, lead time, and the particular measures that these systems can estimate is a great challenge scientifically and practically.
end partial quote from:

http://www.eoearth.org/view/article/51cbf0c17896bb431f6a2eeb/ 

One of the things I have been looking at is the fact that just before the 1861-62 floods in California and surrounding states, there were about 10 to 20 years of droughts similar to what we are experiencing right now. So, hopefully this isn't a harbinger of the Next 1861-62 type of Arkstorm coming to us within 20 years time.

Another potential indicator to me is the recent flooding in Texas where they moved from complete drought and dry washes to 40 high walls of water washing away hundreds of homes in Texas and Mexico. This also looks a lot like what Atmospheric rivers might do if set loose under the right conditions too.

So, this might be another indication of the growth or coming back of atmospheric rivers in ways beyond what people are used to here in California or throughout the U.S.