Premise[]
Angel, Willow, Faith and Conner endure a blast.
Calc[]
Angel's height = 185 cm = 137 px
185 / 137 = 1.35036496 cm per px
explosion diamater = 1284 px = 1733.86861 cm or 17.3386861 m
Raidius = 866.934305 cm or 8.66934305 m
W = 8.66934305^3*((27136*1.37895+8649)^(1/2)/13568-93/13568)^2 = 0.0523653585 Tons (Small Building level)