I am surprised the greenest state in the union has not yet learned anything from these events in the past.
As it has been their history the mud slides get started after a large wildfire clears out major areas of forest and brush and with nothing to absorb a major rainfall and nothing holding the ground back, the water is shed and eventually starts to move more and more earth with it.
After a major Wildfire is over, a simple program of re-seeding it with grasses and some of the natural trees that were there in the first place would solve this problem. A major undertaking it is but look at the cost of the failure to act.
Additionally, selective cutting of forest areas to allow for fire breaks would stop or limit the wildfires and/or increase the ability of firefighter to get control.
However sorry I am for those affected, It is you state and taxes, but do not ask for my help or taxes when you have done nothing to help yourself.