Massive crash only checks the the hit bubble on icehowl so if while hes prepping to charge you run towards him you'll completly avoid the crash whilst making everyone in the raid shit themself.
I haven't had the chance to test this in ToGC, without a speed boost.
I have however used the warrior ability charge in ToGC while hes doing his massive crash and that worked, same with sprint, blink and priest body and soul.