What's your favorite animated explosion in classic animation? - Forum.
To nominate my favorite: The explosion in [tom] "The Missing Mouse" with flying colors, occasionally firework-like sparks and such
When I think about explosions in classic animation, two shorts come to mind: Blitz Wolf and Yankee Doodle Mouse, both of which got exceptional sound editing and I consider very "explosive" films. Upon watching them, the great effort/budget put into them by MGM really shows.

Specifically, in Blitz Wolf:
- the fireworks (?) and shots of the epic entry of Adolf Wolf and
- the (now controversial) scene of Doolittle's response to Pearl Harbour (shot by the LONG DARN THING) right after almost 1 minute of drum-roll suspense music.

And in YDM, the explosions I remember are:
- the explosion of the "tiny dynamite, big boom" gag, and
- the gorgeous scenes of the fireworks that break the wall partially and start chasing Jerry.
I always come to TTTP in Exile in the hope of finding news about Warner announcing Tex Avery Collection.