The University of Oregon said Tuesday that it would investigate last weekend’s trashing of Northern California’s Lake Shasta that apparently occurred during an unsanctioned, but traditional, frat and sorority trip.

The Oregonian reported that it has not been confirmed that Oregon students were at the site, but photos from the site show glaring evidence: items with the school’s logo were found amid the ice chests filled with food and alcohol and 90 tents left behind.

“The manner in which the forest was left was absolutely unacceptable and disgraceful,” Robin Holmes, the university's vice president for student life, said. The paper said national fraternity Zeta Omicron Zeta was suspending all of its chapters until the “situation is addressed.”

Some frats at the school are discussing going to the area to help with the cleanup.