Blue lasers burn the best. Reflective surfaces will stop a laser in its tracks from burning anything. The darker the color, the more likely to burn. I also wonder if the solar panels acted as a receiver for the laser and maybe pumped too much voltage back into the power grid. Voltage should go up as they collect more power but not sure if that was related to the cause. Could be too much power came through the meters on the solar panels and caused the power company to surge the power and then smart meters to start blowing up. I didn’t believe the laser theory but the speed of the fire does make sense if it’s being pointed via a laser and misses random objects. Things still burn after being hit if powerful enough. Solar panels likely reflect some light and are not black, more blue on the best kind. Objects also heat up as they collect laser light until being burnt. If small clouds changed the focus, it could also explain why some trees burned from the inside I believe