I was thinking... what if Sea Wave | Ocean Wave both starts with Acceleration on them?
I find it appropriate thematically, the more a wave lasts, the more destructive it becomes, but eventually it should disappear anyway.
The stats could be
Sea Wave 0
2|0
Gain
when played.
Gain +2|-1 each turn.
Ocean Wave 1
2|1
Gain
when played.
Each turn
is generated.
Gain +2|-1 each turn.
EDIT: or maybe only Ocean Wave could be accelerated, while Sea Wave don't.