According to the comic, the mountains of Nidavellir are the size of moons. In the image, the mountain closest to the storm is about 135 px tall while the storm itself has a length of 1160 px and its thickness is 86 px. Our own moon has a diameter of 3478.8 km or 3478800 m.
3478800/135=25768.8888889 m/px
1160*25768.8888889=29891911.1111 m
86*25768.8888889=2216124.44445 m
The density of clouds is about 1.003 kg/m^3.
3.14*29891911.1111^2*2216124.44445=6.2177199e+21 m^3
6.2177199e+21*1.003=6.2363731e+21 kg
Using the CAPE Method, I'll assume the storm is of strong instability, so 4 kj/kg
6.2363731e+21*4000=2.4945492e+25 j (Multi-Continent level)
Using the Condensation/Evaporation Method, the latent heat of evaporation of water is 2264705 j/kg
6.2363731e+21*2264705=1.4123545e+28 j (Multi-Continent level)