More than 500 Mandurah students were told not to come to school today after the roof was blown off two classrooms at Assumption Catholic Primary School.
Principal Geri O'Keefe said the roof of a senior block building in the school, situated on Gordon Road, lifted and rolled back in gale force winds about 2.30pm yesterday.
"Parts of it did fly through the air for about 70m and some of it landed in a Year 1 playground area which was quite a long way away," she said.
Ms O'Keefe said the damage was being assessed this morning and she hoped classes could be moved to the hall tomorrow so teaching could continue.
"The staff are all here and we're all in work clothes and we're doing a big clean up," she said.
"The best thing was that it happened on a Sunday afternoon and not at 2.30 on a Monday, somebody would have been hurt for sure."