Cal. Educ. Code § 46390

Where a school in a district maintaining more than one school is closed for a part of a term by order of a city or county board of health or of the State Board of Health, or because of fire, flood, impassable roads, epidemic, or other emergency, or by an order provided for in Section 41422, the average daily attendance of the school shall be estimated separately, as provided in Section 46392, and added to the average daily attendance of the other schools of the district.