Why COVID-19 cases are spiking in California and US

People spend Memorial Day weekend at the beach during the coronavirus disease pandemic in Huntington Beach, California, U.S., May 23, 2020. Credit: REUTERS/Patrick T. Fallon TPX IMAGES OF THE DAY.

This week started with California reporting more than 6,000 new cases of coronavirus a day. That’s a record. Despite early sheltering-at-home policies and the current statewide mask mandate, what happened?