I can tell you why - Without rain and after a very hot summer, fuels became extremely flammable. All it takes is one spark to start a fire - from a chain dragging on the ground behind a car/truck, from sunlight shining through broken glass, from some idiot not following safety protocol when doing yardwork, from a homeless person trying to stay warm, (to name but a few). Strong winds fan that spark into a fire within seconds. Embers from the fire are spread in the wind to other dry areas, and the cycle continues. Within 15-30 minutes you have a raging wildfire. When a wildfire gets into a "housing project" (residential area where houses are close together), there's nothing to prevent it from jumping from house to house (houses are made from dry wood).
With no air support (planes are grounded in high wind events), it is virtually impossible to contain a raging wildfire. No amount of water can help.
In the past I have seen news clips of people holding a garden hose while standing in front of a large fast moving wall of flame and smoke and saying they are going to stay and protect their property. Cheers!