You'll have to postpone those beach plans as Hurricane Isaias has closed Miami-Dade Beaches. Mayor Carlos Gimenez has announced all beaches within the county will close on Friday night as the tropical storm is now posing a threat to South Florida. Editor's Choice: 6 Scenic Bike Trails In Florida That Will Bring You To Total Tranquility “ All county parks will close by 8 p.m. Friday Miami-Dade County The storm grew rapidly during the day Thursday, blossoming from just a wave into a hurricane by the afternoon. In addition to the beaches, Miami-Dade County is also shutting down COVID-19 testing sites at the close of business today. Hurricane Isaias is forecast to pass by South Florida as a Category 1 hurricane.