Silver Tsunami

When the amount of elderly people is noticeably higher than the amount of teenagers and children.

John: Yeah dude, there’s like no youth at my church, it’s all grandmas and grandpas.
Mike: Well bro, seems like there’s a silver tsunami in your church.

or

Aidin: There’s so many older people in this nursing home. It’s so sad.
Paul: I think what’s even more sad is the silver tsunami that hit us.