In Gen 5 and onward, yes.
Mega Glalie's Explosion, plus STAB, plus Refrigerate, gives you (250*1.5)1.3, equaling 487.5.
However, this is beat... by Explosion.
In Generation 4 and earlier, Explosion ignored half of the target's defense, giving it an effective Base Power of 500.
Couple this with STAB, and you get a whopping 750 base power!