SOUTH FORSYTH — A suspicious person in the area near Riverwatch Middle School prompted a precautionary lockdown of the campus Wednesday afternoon.

The school off James Burgess Road issued a code yellow lockdown about 2:40 p.m. that lasted for about 30 minutes, according to Jennifer Caracciolo, Forsyth County Schools spokeswoman.

The lockdown did not disrupt dismissal, she said.

In an email sent to parents, Principal Kathy Carpenter wrote: “During a code yellow lockdown, instruction is not interrupted. Students stay inside their classrooms [to allow] time for school staff to account for everyone on campus. At 3:10 p.m. it was determined that this person was not a threat to the school, and students resumed their normal activities.”

Settles Bridge Elementary School parents were also notified, Caracciolo said, but no lockdown was necessary at the campus next door because school had already let out.

Code yellow is one of four distinctions the district uses to identify and handle potential or real threats to students and staff on campus. Before yellow comes code green, which indicates normal school operation.

A medical lockdown — previously called code blue — does not disrupt classes and is used to ensure unobstructed access to the patient by medical staff.

A code yellow means a potentially dangerous situation exists outside the physical building. During this level of security, anyone on campus is asked to return to their classrooms and offices, which are all locked.

Outdoor activities are suspended, but classes continue as usual.

Doors are only to be opened for students, administrators or law enforcement.

A code red indicates a possible life threatening or actual crisis is occurring inside the school. This would be the procedure for an active shooter situation or any other actual dangers, during which time doors are not to be opened for anyone until the situation is cleared.