Games are super snowbally because...

Because matchmaking is atrocious right now. Last game for example my team destroyed the enemy. I take a look what everyone's skill is and I see the enemy mid is a first time ranked player, probably just after hitting level 30. She got destroyed (I'm mid gold).

A game before that my team got destroyed. The enemy graves was P5 with s6 D5. It showed because he was impossible to be dealt with.

I usually don't check sites like Lolnexus but found that a lot of matches are really unbalanced.

This also causes another issue: toxicity. Due to matches being unbalanced and very one-sided it causes people to be frustrated and toxic.

I don't know enough about the system to have a solution but I believe something has to be done.