Evolutionists believe that the material in coal beds accumulated over millions of years in quiet swamp environments like the Everglades of Florida. Hence at least 33 Noah's Floods are needed, staggered in time, to generate our known coal beds. Therefore a single Noah's Flood cannot be the cause of coal formation. This argument is based on valid estimates of the volume of vegetation currently on today's land surfaces.
Modern research shows that less than two metres of vegetation are needed to make one metre of coal.
Two other factors are very relevant here. In addition, there are the vast icy wastes of Antarctica beneath which are rock layers containing thick coal beds. But this all assumes that the area of land surface available for vegetation growth has always been the same. This assumption simply is not correct. But there is another way of comparing vegetation growth and volume with the known coal beds, a way that is probably far more reliable, and that is by comparing the stored energy in vegetation with that in coal.