Three cases at Summit Middle School Four cases at a teenage social gathering in Breckenridge Four cases at an adult social gathering in Breckenridge Two cases at DoubleTree by Hilton hotel in Breckenridge Two cases at Breckenridge Mountain Information at Breckenridge Ski Resort Three cases at an adult social gathering in Silverthorne Two cases on a youth lacrosse team in Silverthorne Two cases on ski patrol at Keystone Resort Five cases at an adult social gathering in Copper Mountain Two cases at Summit Middle School School data Two quarantines were issued on Sunday, April 4, at Frisco Elementary because of positive cases.