I read this as in Finland you can get 30cm snow in a day. And the second person is comparing that to 600cm in a year. Am I right?

Total accumulation matters in roof design, not single-day dumps. The mountain I'm referring to (and others like it) can get 100cm+ single day, but that's not super common.

Helsinki, for example, only gets a total of ~90cm a year. So the mountain sees more snow in a single event some years than Helsinki all year.