A Public Safety Power Shutoff is the name that the utility Pacific Gas and Electric (PG&E) uses to describe a proactive shutoff of electricity.  PG&E may declare a PG&E power shutoff if some of the following weather conditions exist:
A Red Flag Warning
Low humidity levels
Forecasted sustained winds generally above 25 miles per hour and wind gusts in excess of approximately 45 miles per hour
Dry fuel conditions