On Wednesday, August 2, 2017, at around 10:23 AM, the west-central portion of the Upper School exploded from a natural gas leak while construction crews were working to move a gas meter. Two staff members died, and nine people were injured, one critically. The high school opened in temporary quarters in Mendota Heights for the 2017–18 and 2018-19 school years. Demolition began in December 2017, and reconstruction of the new structure on that same site was completed in time for the 2019-20 school year.