Chimney fires can burn explosively and are generally noisy and dramatic enough to be detected by neighbours or people outside. Victims of them compare the sound of the fire to a low rumbling noise like a train or low-flying airplane. Flames have been known to shoot from the top of the chimney accompanied by dense smoke. The first indication of a chimney fire is usually the noise (a roaring sound) that grows louder as the fire intensifies, reaching temperatures of up to 1200 degrees C. Chimney fires can have flames and sparks that shoot a few meters from the pot or top of the chimney.
Not all chimney fires are dramatic, some chimney fires that lack air (oxygen), heat or fuel, can still cause issues, and can still burn at high temperatures, and should combustible materials be near the chimney (in the loft for example) they can ignite.