Some calculations that would help in the Potter-Verse revisions.
Dumbledore's water attack
It is hard to pixel-scale this image. The water was able to contain Voldemort. I think it's safe to assume it's diametre is at least two Voldemorts.
Voldemort is described as "tall", but not "very tall" in the series, so he should be around 5'10", or 177.8 cm. Density of water is 1000 kg/m^3.
4/3*pi*1.778^3*1000 = 23 544.2 kg of water
Dumbledore was able to throw all that water at Voldemort before he could react. I suppose 30 m/s would be a reasonable assumption? Attempting to find the exact speed of the water would take ages and I can't even think of a method to do so.
23544.2*30^2*0.5 = 1.0594890e7 Joules, Wall level+
Not too impressive.
Let's assume Dumbledore was around 10 metres from the water thing that trapped Voldemort inside.
The water is 97 px in diametre. Panel height is 166 px.
2atan(97/(166/tan(70/2))) = 30.9513759 degrees
Since we have angle and distance we can solve for size. That's 5.5374 m, or 2.2687 m in radius.
4/3*pi*2.2687^3*1000 = 48 912.5 kg of water
48921.5*30^2*0.5 = 2.2014675e7 Joules, Wall level+
The shockwave seemed to reach Dumbledore who fell to the ground.
Dumbledore: 103 px or 180.34 cm
Panel height: 166 px
2atan(103/(166/tan(70/2))) = 32.7659836 degrees
3.0671 m between them.
E = (ρ/t^2)*(r/c)^5
ρ = 1.225 (density of air)
c = 1.05
r = 3.0671
t = 3.0671/340.29 = 0.009
(1.225/0.009^2)*(3.0671/1.05)^5 = 3 216 208.93719 Joules, Wall level
This is an extreme low-ball.
Assuming the shockwave covered the entire hall.
According to Wikipedia, the place where the Atrium was filmed is over 200 feet long or 60.96 m. The radius of the shockwave should be at least 30.48 m.
t = 30.48/340.29 = 0.09 seconds
(1.225/0.09^2)*(30.48/1.05)^5 = 3.1173056580745808588e9 Joules, or Building level
The high-end seems far more reasonable to me.
I'll assume the shockwave covered the Great Hall.
Some dude on reddit calculated the dimensions of the Great Hall. It's 145 feet long or 44.196 m.
t = 22.098/340.29 = 0.065
(1.225/0.065^2)*(22.098/1.05)^5 = 1.19709254515e9 Joules, Building level
Aurors repairing a bridge
Aurors repairing a building
It was going to burn down Paris yada yada yada. I've done a rough calculation and it's 7-A.
So Grindelwald can deal 7-A damage over-time. We cannot turn range into yield, however. The fire can only spread over-time, but the initial fireball was far less powerful. So I will try to estimate the size of the original fireball.
4/3*pi*21.5^3 = 41629.77 m^3
Grindelwald's in the middle, though, he'd had to keep himself safe. So assuming a cylinder in the middle with a radius of around 10 m to keep Grindelwald himself safe:
pi*10^2*43 = 13508.84 m^3
41629.77-13508.84 = 28120.93 m^3
That's 7428763.7923 gallons.
418400/32*7428763.7923 = 9.71310865843e10 Joules, City Block level
That's a nice supporting feat.
Revised version by Blademan9999 and Therefir:
Fire like air obeys the ideal gas law. So like air it's density will depend on it's temperature. The 0.3g/l density is for fires at everyday temperatures, not 3000C fire.
So the density of this fire should be = 1.225kg/m^3*288C/3273C=0.10779kg/m^3.
He recalculated Grindewald's feat using the density of blue fire, but I still have a minor problem on how you calculated the volume. You assumed a cylinder in the middle with a radius of 10 meters around Grindelwald, but going by the video, it's actually a lot smaller than that.
Cylinder volume = pi*4.93^2*43 = 3283.31 m^3
Fire volume = 41629.77-3283.31 = 38346.46 m^3
Density = 38346.46*0.1078 = 4133.75 kg/m^3
Energy = 4133.75*2984*919 = 11335966090 Joules, 2.71 Tons of TNT (Large Building level)
Five Aurors used Finite to force Grindelwald's fire back and undo it. I guess I'll divide the yield by 5 to find the AP of each Auror.
9.71310865843e10/5 = 1.942621731686e10 Joules, Large Building level
There were several issues, for example it's grams, not gallons, the fire being less dense as it is blue fire and the volume of the fire. Therefir recalculated it here to be 2.71 tons of TNT.
So for the high-mid tiers it's 1.093 tons of TNT, Building level (scaling to Dumbledore's fire).
The mid-tiers are 2.71/5 = 0.542 tons of TNT, Building level (countering Grindelwald's fire),
The low-mid tiers are 1.093/3 = 0.364 tons of TNT, Building level (scaling to the high-mid tiers).