Fire in a chimney in August? Odd! I've lived in this house for 39 years and NEVER built a fire in my wood burning stove in the month of August.
We do not burn any papers in our wood stove; everything that needs to be destroyed is shredded, and/or burned outside. If papers were burned in the stove, and there just happened to be leaves, pine needles or a nest inside the chimney, I can see a fire hazard.
However, if the chimney was built correctly like mine, it would've been a solid 4 walled brick chimney with the insulated stove pipe venting thru a clay thimble. If I have a chimney fire, it would be contained in the brick chimney.
A lightening strike hitting Rachel's house makes the most sense. We had damages from a lightening strike in July.