As a former firefighter, I can attest that there is nothing wrong with the firefighters.  These fires are called firestorms.

"A "firestorm" is a large, intense fire that generates its own wind system, creating strong winds that blow towards the fire, fueled by the rising column of hot air from the burning area, essentially sustaining the fire's intensity and rapid spread; it's often associated with large wildfires or major urban fires where the heat creates a powerful updraft, drawing in fresh air to feed the flames."

The only way to stop a firestorm is to create a firebreak where all of the fuel is removed.  Bulldozers and other heavy construction equipment are traditionally used in conjunction with massive water drops to create the firebreak ahead of the fire.  When the fire reaches the firebreak, and there is no more fuel, it burns itself out. 

Unfortunately, firestorms of this magnitude in congested urban areas are impossible to stop using conventional means.