The Centers for Disease Control and Prevention (CDC) announced on Friday that 13 counties in California, roughly one-quarter of the state, have reached ‘High’ levels of COVID-19 and are recommended a return of indoor masking in those counties.

All 13 counties are located in Northern California, including the Counties of Del Norte, El Dorado, Marin, Mendocino, Monterey, Napa, Placer, Sacramento, San Benito, Santa Clara, Solano, Sonoma, and Yolo. According to the CDC, hospital bed capacity, newly admitted COVID-19 patients per 100,000 residents, and the total number of new cases per 100,000 in a county are used to rank where a county stands.

Under that metric, in counties with more than 200 new cases per 100,000 residents in the past week, COVID patients admission where it is over 10 per 100,000 are officially listed as high. On Friday, those 13 counties went above that 10 threshold, including Sacramento with 12.1 per 100,000, Sonoma and Marin Counties with 11.8, and Solano County with 11.5.

Read more at California Globe