3 How do you notify others? Tornado sirens are outdoor warning systems to alert people to go to shelter, preferably in a nearby building. The sirens often cannot be heard inside a building so you should have an indoor warning system as well. Use multiple notification methods to contact everyone • Weather Radio • Local Media • Calling tree • Intercom or emergency alert system • Door to door notification • Text or E-mail • Network broadcast message • Do not activate the fire alarm! Identify the most effective notification process to meet the needs and challenges of your building or department.