I'm no expert, but I don't find the way it spread unusual. The attic was wood -
very, very old wood - the roof was wood. Add in the wind and the unfortunate delays that firefighters encountered in getting there and it becomes a recipe for disaster. Still, by all accounts (credible sources, anyway), they did an outstanding job of putting out the fire, saving artifacts, and if I understand correctly, limiting injuries to just one firefighter out of 400-500. I have no doubt that all aspects (cause, response, etc.) will be studied in depth for years to come.
Yes, it will be interesting!