About Disaster Days

Methodology, data and credits

CalMatters is a nonpartisan, nonprofit journalism venture committed to explaining how California’s state Capitol works and why it matters. If you have any questions about the database, discover any errors or have interest in the data, which is available upon request, please email ricardo@calmatters.org.

Ricardo Cano

Ricardo Cano

K-12 Reporter

John D'Agostino

Mohamed Al Elew

Data intern

John D'Agostino

John D'Agostino

News Developer


Methodology and Data

In California, school districts that close schools for emergencies can request that the California Department of Education protect their attendance-based funding. Such requests, known as Form J-13A waivers, must list the closed schools, dates, number of lost days and reason for the emergency. Using the California Public Records Act, CalMatters compiled the 17 years of these requests on file with the department to build a school-site level database of reported school closures.

Reported closures were manually coded into five categories: wildfires, natural disasters and weather, student safety, infrastructure and other. Coding was further refined to specify reasons for closures, such as the 2018 Camp Fire or the 2011 California windstorm. State enrollment data for the year of each reported closure was matched with each school site to quantify the student impact. CalMatters omitted closures where enrollment could not be verified for the reported year.

Closure days were defined as one lost day of instruction at a single public school site. Schools that did not report any closures were not included in the database. The interactive map shades each school district by closure days per the number of schools in the district as of the 2018-19 school year. Closures for schools in districts that merged during the extent of the dataset are included in their current district. Districts not present in current federal maps are not included in the interactive map.

School districts self-report their closure information to state education authorities, who hand-enter it into a database for internal use. For this reason, it may contain errors and inconsistencies. Because the state does not specify a deadline for requesting J-13A waivers, some districts submitted multiple school closure incidents on a single request, or submitted multiple requests for a single incident. In these cases, CalMatters manually cleaned and sorted the data.

Some school districts that experienced system-wide closures reported that “All Schools” closed rather than delineating each affected school site. For these records, CalMatters used the state’s directory of public schools to identify schools in operation under the corresponding school district during the school year for which that waiver request was submitted.

The state enacted a lower instructional time requirement for schools during the years of the recession, from 180 to 175 instructional days between the 2009-10 and 2014-15 academic. This temporary change in instructional time requirements may have led to some reduction in the number of emergency school closures reported to the state through the J-13A waiver process for those years, according to state officials.

School districts in California are able to budget “emergency” or “snow” days in their academic calendars, though are not required to under state law. School closures that districts were able to make up using built-in emergency days are likely not included in CalMatters’ database.

Though the database includes some closures that were not waived by the Department of Education (closures to mourn the death of President George H.W. Bush in Klamath-Trinity, for example), most requests were approved by the state.