Calc Elder Scrolls Legends - Fireballs explode near Winterhold

0:39
Several huge fireballs explode, seemingly from Alduin (though perhaps also mages going by the dialogue).

The Elder Scrolls Legends - Heroes of Skyrim Trailer said:

...to Scolars of voracious and ferocious magic...and to dark terrors from above.

Click to expand...

0:11
The average height of a Norwegian man is 179.9cm, or 1.799m (closest equivalent to a Nord I could find).

184 pixels = 1.799m
1 pixel = 1.799m/184 = 0.00977717391m
0.00977717391m X 497 = 4.85925543m
Timeframe is 0.19 seconds.

17 pixels = 4.85925543m
4.85925543m/2 = 2.42962772m
1 pixel = 4.85925543m/17 = 0.285838555m
0.285838555m X 66 = 18.8653446m
18.8653446m/2 = 9.4326723m
0.285838555m X 103 = 29.4413712m
29.4413712m/2 = 14.7206856m

We can use Nuke Map, and for a radius of 14.7206856m, we get a yield of 0.0147 kilotons (or 14.7 tons of TNT), which I think is far more reasonable. How about speed?
Timeframe is 0.32 seconds.

15 pixels = 4.85925543m
1 pixel = 4.85925543m/15 = 0.323950362m
0.323950362m X 674 = 218.342544m

T = 218.342544m/0.32s
= 682.32045/340.29
= Mach 2.00511461

Final Results
Fireballs explode near Winterhold (energy) = 14.7 tons of TNT
Fireballs explode near Winterhold (speed) = Mach 2.005