Pine Beatle population is partly controlled by how cold of a winter one gets: "However, unusually hot, dry summers and mild winters throughout the region during the last few years, along with forests filled with mature lodgepole pine, have led to an unprecedented epidemic" - https://en.wikipedia.org/wiki/Mountain_pine_beetle

It's not really about extreme events as defined in the paper you reference ("events that are several standard deviations away from the average of the distribution by which they are measured and described") by their nature very extreme events are rare. So whether California has gotten more or less floods isn't relevant.

https://www.nasa.gov/feature/goddard/2016/climate-trends-con...

Specifically check out California here: https://www.ncdc.noaa.gov/temp-and-precip/state-temps/

http://www.nrcan.gc.ca/forests/fire-insects-disturbances/top...

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2010....