California Code, Family Code - FAM § 3424

(a) A court of this state has temporary emergency jurisdiction if the child is present in this state and the child has been abandoned or it is necessary in an emergency to protect the child because the child, or a sibling or parent of the child, is subjected to, or threatened with, mistreatment or abuse, or because the child has been unable to obtain gender-affirming health care or gender-affirming mental health care, as defined by Section 16010.2 of the Welfare and Institutions Code.

(b) If there is no previous child custody determination that is entitled to be enforced under this part and a child custody proceeding has not been commenced in a court of a state having jurisdiction under Sections 3421 to 3423, inclusive, a child custody determination made under this section remains in effect until an order is obtained from a court of a state having jurisdiction under Sections 3421 to 3423, inclusive. If a child custody proceeding has not been or is not commenced in a court of a state having jurisdiction under Sections 3421 to 3423, inclusive, a child custody determination made under this section becomes a final determination, if it so provides and this state becomes the home state of the child.

(c) If there is a previous child custody determination that is entitled to be enforced under this part, or a child custody proceeding has been commenced in a court of a state having jurisdiction under Sections 3421 to 3423, inclusive, any order issued by a court of this state under this section must specify in the order a period that the court considers adequate to allow the person seeking an order to obtain an order from the state having jurisdiction under Sections 3421 to 3423, inclusive. The order issued in this state remains in effect until an order is obtained from the other state within the period specified or the period expires.

(d) A court of this state that has been asked to make a child custody determination under this section, upon being informed that a child custody proceeding has been commenced in, or a child custody determination has been made by, a court of a state having jurisdiction under Sections 3421 to 3423, inclusive, shall immediately communicate with the other court. A court of this state which is exercising jurisdiction pursuant to Sections 3421 to 3423, inclusive, upon being informed that a child custody proceeding has been commenced in, or a child custody determination has been made by, a court of another state under a statute similar to this section shall immediately communicate with the court of that state to resolve the emergency, protect the safety of the parties and the child, and determine a period for the duration of the temporary order.

(e) It is the intent of the Legislature in enacting subdivision (a) that the grounds on which a court may exercise temporary emergency jurisdiction be expanded. It is further the intent of the Legislature that these grounds include those that existed under Section 3403 of the Family Code as that section read on December 31, 1999, particularly including cases involving domestic violence.