If water had its way, this is what California would look like:
Think about it for a second. Every single moment, currents of air move, slowly or rapidly, across every land surface on the planet. Anything loose gets blown slowly or rapidly, to lower places. Every now and then, in some places rarely and in other places commonly, liquid water falls from the sky on almost every land surface on the planet. Now and then, in certain limited areas, frozen water builds up to great heights, thousands of feet hight, and moves along, scraping deep hollows and grooves the size of big lakes out of these land surfaces. Now and then the earth shakes and stuff falls down. Most of the earth’s surface is ocean, only a small percentage is land. With all this blowing and washing and scraping away, you would think that all the stuff on the land would eventually end up in the ocean and all of the land would look like this:
There are several reasons this does not happen. One is that mountain building happens because continental shelves push against each other. Another is that volcanoes occasionally spew ash, lava, and stuff out onto the land surface. Also, there is another, less often known about by the average person but incredibly important reason that the land does not look like this ...
Underneath the land there is melty-squishy-hot stuff that tends to push upwards a little bit almost everywhere, and a lot in some places, though it is usually pushed back upon by the weight of the land itself. If you remove a bunch of stuff from the surface of the continent, this pushing gets a bit of traction. So, if you have a big piece of continent with erosion happening all the time on the top, this pushing will happen from below, and the continent will not disappear below the surface of the sea. The Congo basin is probably an example of this. It rains a lot, there is constant erosion. So, the land surface across most of the Congo has been eroding for something like a couple or few hundred million years, at least, like it is now. As the surface is eroded away, the underneath slowly rises. So now, much of the Congo basin has deeply eroded rivers, and all the hills between the rivers are made of stuff that is like granite, the cooled down, hardened melty-squish-hot stuff. In fact, a lot of Africa is like that.
In California, the last calendar year was the driest one on record. California has been so dry over the last few years that it is nearly dried out. The reservoirs are puddles, the groundwater is a mystery, and the state is in a state of crisis. But today, the first Pineapple Express of the rainy season arrived, and dumped huge amounts of rain in parts of the state.
California is uplifted. Unlike Louisiana, Mississippi, and nearby areas, which are all very close to sea level, California stands up high over the ocean. When you head for the ocean from inland, depending on where you start, you may have to cross significant mountain ranges or linear arrangements of tall hills, and just before getting to the sea you will have your brakes on a lot of the time because you’ll be going down hill. The shoreline of California is roughly synonymous with the continental shelf, in contrast to other coastlines in the US where the shelf edge may be hundreds of miles out to sea.
The dry conditions over the last few years have resulted in a lot of fires on the hills in this hilly, uplifted country. The geological stuff underneath the surface in much of California is not like the deep hardened magma of the Congo, or for that matter, New Hampshire, Maine and the Maritimes. It is soft, to varying degrees. The top, exposed areas on those hills is made of rocks and dirt. When torrential rains flow over the surface, this material is held in place by a combination of plant roots and luck. The force of the rains is attenuated by the upper parts of the vegetation. But with the vegetation either burned off or dead(ish) from drought, or both, the water washes away the softer smaller particles, leaving the larger stones and rocks exposed, and rivulets start to form and erosional gullies deepen and widen. Meanwhile the ground soaks up water and becomes both loose and heavy at the same time. All these factors together constitute a step in the process of making California look, eventually, like this:
And if your house, or the road to your house, or anything, is in the way, it will get washed down stream or buried under other stuff washing down stream. For this reason, evacuations are underway in parts of the Sunshine State.
There’s good news, though. Even though the forces of nature seem intent on making California eventually look like this:
There are other forces of nature that are intent on making California look like this:
That’s the good news. The bad news is that those other forces are, well, earthquakes.