Situational irony is where an idea comes into play that completely contrasts the idea of the situation,
So, in this instance, we are talking about a hairdresser. As most people know, they are supposed to be good at styling hair and are expected to apply this to themselves as well.
But, in this scenario, it mentions the hairdresser has an awful hairstyle herself. This is ironic because this could probably mean the person getting their hairstyle could end up with the same, awful look.
