Historical clue formulations

• Signal of impending danger — 2024-12-07
• [Urgent! Urgent!] — 2022-07-12
• "Warning!" — 2022-01-14
• State of emergency — 2017-03-03
• Time for crisis management — 2011-12-17
• Klaxon-sounding occasion — 2009-10-17
• "Danger!" — 2008-03-01
• Warning on the Enterprise — 2000-02-29
• Serious warning — 1999-12-04
• Period of crisis — 1999-10-29
• "The enemy is upon us!" — 1999-02-19
• Pre-meltdown signal, maybe — 1998-06-05
• State of high alarm — 1997-09-23
• State of emergency — 1996-07-12
• Danger signal — 1994-11-26