Missing mass isn’t a sin if it’s obviously impossible to attend Mass, as missing Mass in those circumstances isn’t a deliberate disobedience of the commandment of God.
These conditions must be genuinely true in order that sin isn’t committed…Illness, dangerous weather, lack of a priest or Church within reasonable distance, small infants, the necessity to stay with a sick relative and no-one to relieve you for an hour or two, and shift work can all cause you, through no action or inaction of your own, to miss Mass.
These conditions are drawn from the Catholic Catechism of the Catholic Church with has the present Pope’s imprimi potest when Archbishop