Sand
People think tsunamis are only made of water but they have a few pieces of sand in there too. There's actually more sand in the ocean than most people think. And tsunamis can't just have water and sharks in them. A few grains of sand will always slip in.
さ, しゃ
すな, よなげる
None
How do I know there's sand in there? Because I saw (さ) them!