Overview
Exigent circumstances, as defined in United States v. McConney are "circumstances that would cause a reasonable person to believe that entry (or other relevant prompt action) was necessary to prevent physical harm to the officers or other persons, the destruction of relevant evidence, the escape of the suspect, or some other consequence improperly frustrating legitimate law enforcement efforts."
Application
Exigent circumstances are essentially exceptions to the general requirement of a warrant under the Fourth Amendment searches and seizures.
In Missouri v. McNeely (2013), the Supreme Court clarified, "A variety of circumstances may give rise to an exigency sufficient to justify a warrantless search, including law enforcement's need to provide emergency assistance to an occupant of a home . . . engage in “hot pursuit” of a fleeing suspect . . . or enter a burning building to put out a fire and investigate its cause."
Courts will typically look at the time when the officer makes the warrantless search or seizure to evaluate whether at that point in time a reasonable officer at the scene would believe it is urgent to act and impractical to secure a warrant. Courts may also consider whether the facts suggested that the suspect was armed and planning to escape, whether a reasonable police officer would believe their safety or others’ safety was threatened, and whether there was a serious crime involved.
Exigent circumstances may also occur when the police is in hot pursuit of a suspect who is possibly involved in criminal activities and in the process of fleeing. (See Michigan v. Fisher, 558 U.S. 45 (2009))
Further Reading
For more on exigent circumstances, see this Hofstra Law Review note, and this Missouri Law Review article.
Illustrative Cases
See e.g., People v. Smith, 46 Cal.App.5th 375, 260 Cal. Rptr. 3d 68 (Cal. Ct. App. 2020); and United States v. Ackerman, 831 F.3d 1292 (10th Cir. 2016)
[Last updated in December of 2022 by the Wex Definitions Team]