Credit to +Man from Shadow and +Saisho on Google+.
Feat
Edrad pretty much nukes Ikkaku with a huge pillar of fire and Ikkaku blocks that with little difficulty:
Volume Destroyed
Window=3 Pixels=1 m
Explosion Diameter=235 Pixels=78.3 m
Explosion Radius=39.7 m
Ikkaku's Legs=381 Pixels=Half of Ikkaku's Body=0.91 m.
Crater Height=849 Pixels=2.02779527559 m
We'll be modelling the crater as a cylinder. The width of the crater may not be 100% even but that can be chalked up to Ikkaku absorbing most of the impact. The explosion was pretty much a cylinder anways.
Volume=10,044.533261414585 m^3
Energy
There was steam coming from Edrad's fist and the crater, so we'll apply vaporisation:
10,044.533261414585×1,000,000×25,700=258,144, 504,818,354.8345 Joules
61.698017404004502851 Kilotons of TNT
Town level+
Edit:
Resurrección Edrad and Bankai Ikkaku should be at least this level, as this was very casual.