From Southern California Public Radio:

Family members who believe a loved one poses a danger to themselves or others will be able to ask police to seek a temporary “gun violence” restraining order from a judge beginning Jan. 1. The order would allow police to seize the person’s guns for 21 days.

Under the new law, a restraining order could be issued without prior knowledge of the person. In other words, a judge could issue the order without ever hearing from the person in question, if there are reasonable grounds to believe the person is a threat based on accounts from the family and police.