That question has not been fully answered, cp. You and I know who is at the bottom of this, but as to how he did it, we are waiting to see what the investigation turns up. We do know that it began with very high winds over a large area that first night. My son said he had never experienced such strong winds. He thought parts of the house might come apart. It blew trees down. Some hit power lines and poles which then caused many fires. The wind carried the fires quickly over vast areas burning down everything in its path.
This does not explain why other fires started in the days that followed. Some were not close to the existing fires. When new fires break out, there are no reserves to respond in some areas. Fire fighters from other states are responding. It all happened so quickly. The destruction is pretty bad in highly populated areas.
We have been told there would be many fires in these last days. Prophecy is being fulfilled.