MISSOULA, Mont. -

Officers and first responders participated in an emergency exercise Wednesday at Corvallis High School, south of Missoula.

The scenario for the drill is an active shooter incident that results in numerous victims.

Ravalli County Sheriff Chris Hoffman tells us the drill is designed to let responders and school staff practice plans for school lockdown, rescue, medical triage of victims, and post-emergency reunification of students with parents.

"This type of incident has gotten a lot of attention in the media, and the frequency is up around the nation,” said Hoffman. “Obviously, this is a good way for us to test how we work together as an emergency service community."

Hoffman tells us the exercise took months to plan. He estimates at least 50 people and 50 agencies were involved in the drill.