The Feat[]
Mothra flaps her wings and dissipates a storm. Feat happens here.
Calculation[]
Thickness of Cloud: Typical rain clouds fall under "Nimbrostratus", which can have a thickness between 2,000 and 4,000 meters. As an average i'll use 3,000 meters.
Angsize for Cloud: 2atan(tan(70deg/2)*[149 px/576 px]) = 20.5333557 degrees.
Diagonal Distance to Cloud: 8,281.3 Meters.
Elevation of Cloud: The base of a Nimbostratus lies at about 2,000 Meters ASL. If they are 3,000 Meters thick, then their middle point must lie at about 2,750 Meters ASL.
Horizontal (Overhead) Distance to Cloud (Pythagoras): Sqrt((8281.3^2)-(2750^2)) = 7811.36542 Meters.
Angsize for Oil Rig: 2atan(tan(70deg/2)*[176 px/576 px]) = 24.1529829 degrees.
Height of Oil Rig: 91 Feet (27.7368 meters)
Distance to Oil Rig: 64.82 meters.
Distance from Mothra to Edge of Clouds (Radius): 7811.36542-64.82 = 7746.54542 Meters.
Volume: Pi*(Radius)^2*(Height) = Pi*(7746.54542)^2*(3000) = 565,571,179,679 Cubic Meters.
Density of cloud is 1.003 kg/m3, so Mass: 567,267,893,218 Kg.
Dispersion starts at 00:39 and ends at 00:42, Timeframe: 3 Seconds.
Speed of Dispersion: 7746.54542/3 = 2582.18181 m/s
Kinetic Energy: (567,267,893,218)*(2582.18181^2)/2 = 1.89117554e18 Joules, 452 Megatons.
All Nice and Nuclear.
Final Result[]
Mothra Disperses a Cloud: 7-A, Mountain Level.