Scientifically, the fire and cataclysmic destruction of Sodom and Gomorrah may be explained by an earthquake. Heat, gases, sulphur, and bitumen would have been spewed into the air through the fissures formed during a violent earthquake (14:10). The lightning that frequently accompanies an earthquake would have ignited the gases and bitumen.
The narrator frames the immediate cause, ‘burning sulphur,’ with the ultimate cause, the Lord. It is theologically mischievous to dismiss either the scientific causes of historical events because of theological explanation or vice versa.