Is this the new normal?

Another school shooting, again in Colorado. The news reporter happened to comment that the police used well-rehearsed active-shooter protocols to ensure the safety of the students, staff and general public.

The these types of protocols has evolved since the shooting at Columbine, about 8 miles away, and were also put into place at the Aurora Theater Shooting, about 16 miles away. All three events occurred in Arapahoe county, in the Denver metro area.

There have also been events in nearby Colorado Springs. Is it something in Colorado, or something in our society in general, that makes events like this so common?

This event will probably ignite the gun rights vs gun safety debate, but I would rather not discuss that aspect on this thread.