What's actually causing the Russian wildfires? "Heat & drought" don't CAUSE fires, just make ignition easier!?

The cause won't likely be known until the fires are out, or at least controlled, and a proper origin and cause investigation can be done. That is uming that they can locate the area of origin, and any evidence is intact. Much as a formal homicide investigation doesn't begin during an active shooting, the fire investigation team needs a safe and secure area to begin their investigation.