Emergency alerts are notifications that are used to alert people of an emergency situation. They can come in the form of SIRENS, which are loud, high-pitched sounds that are used to warn people of danger. SIRENS are often used by emergency services such as police and fire departments to alert people of an emergency. They can also be used to signal the start or end of a tornado warning. Emergency alerts can also come in the form of text messages, emails, or other forms of communication.