List of tornado emergencies

Since its initial usage in May 1999, the National Weather Service (NWS) in the United States has used the tornado emergency bulletin — a high-end classification of tornado warning — sent through either the issuance of a warning or via a "severe weather statement" that provides updated information on an ongoing warning—that is issued when a violent tornado (confirmed by radar or ground observation) is expected to impact a heavily populated area, and pose a significant threat to life and property. The tornado emergency wording is issued when reliable sources confirm an ongoing tornado with a catastrophic risk to life and property.

Source: Wikipedia — List of tornado emergencies (CC BY-SA 4.0)