California's grid operator issues level 3 emergency

California ISO declared Energy Emergency level 3, meaning rolling power outages were imminent.

The alert went into effect Tuesday evening before expiring at 8 p.m. that night.

Level 3 is the state's grid operator's highest category of an energy emergency.

The outages are up to the local power companies. The emergency declaration comes as California is asking residents to conserve as much power as possible.

California was also under a flex alert before expiring 9 p.m. Tuesday.

RELATED: Peak electricity use in California expected to reach 20-year high today

During the Flex Alerts, residents are urged to take the following power-saving steps:

  • setting thermostats to 78 degrees or higher
  • avoiding use of major appliances
  • turning off unnecessary lights
  • avoid charging electric vehicles

Residents were also advised to pre-cool their homes as much as possible and close blinds and drapes to keep interiors cool.