Under Pennsylvania law, police officers are required to only conduct searches when they have a valid search warrant.  Through case law, the courts have created a very narrow set of exceptions or excuses to the general warrant requirement.  One such exception is known as exigent circumstances.

Pennsylvania courts have held probable cause to believe contraband is present is necessary to justify a warrantless search, but it alone is not sufficient [ … ]. Mere probable cause does not provide the exigent circumstances necessary to justify a search without a warrant. Id citing United States v. Rubin, 474 F.2d 262, 268 (3d Cir. 1973).  The possibility that evidence may be removed or destroyed is an exigent circumstance exception to the warrant requirement. Dean at 521 citing United States v. Coles, 437 F.3d 361, 366 (3d Cir. 2006).  The officers may not, however, create the exigent circumstances to justify a warrantless search or seizure.