Cal. PEN § 1203.35

(a) (1) In any case in which the court grants probation or imposes a sentence that includes mandatory supervision, the county probation department is authorized to use flash incarceration for any violation of the conditions of probation or mandatory supervision if, at the time of granting probation or ordering mandatory supervision, the court obtains from the defendant a waiver to a court hearing prior to the imposition of a period of flash incarceration. Probation shall not be denied for refusal to sign the waiver.

(2) Each county probation department shall develop a response matrix that establishes protocols for the imposition of graduated sanctions for violations of the conditions of probation to determine appropriate interventions to include the use of flash incarceration.

(3) A supervisor shall approve the term of flash incarceration prior to the imposition of flash incarceration.

(4) Upon a decision to impose a period of flash incarceration, the probation department shall notify the court, public defender, district attorney, and sheriff of each imposition of flash incarceration.

(5) If the person on probation or mandatory supervision does not agree to accept a recommended period of flash incarceration, upon a determination that there has been a violation, the probation officer is authorized to address the alleged violation by filing a declaration or revocation request with the court.

(b) For purposes of this section, “flash incarceration” is a period of detention in a county jail due to a violation of an offender’s conditions of probation or mandatory supervision. The length of the detention period may range between 1 and 10 consecutive days. Shorter, but if necessary more frequent, periods of detention for violations of an offender’s conditions of probation or mandatory supervision shall appropriately punish an offender while preventing the disruption in a work or home establishment that typically arises from longer periods of detention. In cases in which there are multiple violations in a single incident, only one flash incarceration booking is authorized and may range between 1 and 10 consecutive days.

(c) This section shall not apply to any defendant sentenced pursuant to Section 1210.1.

(d) This section shall remain in effect only until January 1, 2028, and as of that date is repealed, unless a later enacted statute, that is enacted before January 1, 2028, deletes or extends that date.