Soft ground is to blame for a 360-ton crane toppling outside a south Edmonton school.

The Edmonton Public School Board says it received reports of the tipped crane outside of Dr. Margaret Ann Armour School at about 9:30 a.m., though it's not clear when the equipment actually fell over. 

A crane operator was performing safety checks on the mobile crane when the crane's left rear outrigger sunk into soft ground, causing it to tip over, according to an email from an Alberta Labour and Immigration spokesperson. 

No one was injured in the incident. 

Occupational Health and Safety officials are now investigating the incident. 

The province says the crane is operated by Excalibur Crane who has retained an engineering company to figure out a plan to right the unit. 

The school has classes from Grades 1 through 9 and students aren't set to return until Sept. 3.