Extreme Precipitation and Storms Data:
The data in the table shows the vulnerability to moisture events. It is important to note that the data is variable and that from decade to decade a county can increase, decrease, and increase again the levels of precipitation and storm events. In addition, some counties are largely affected by extreme precipitation and storms, which are not mentioned in the chart.
To calculate which counties will see an increased risk for precipitation and storm events (defined as events with 2 days of rain above the max historical amount), data was collected from the Cal-Adapt Annual averages and compared to the Historical Baselines. For precipitation, increased risk was calculated by finding the difference between the decadal average and the historical baseline for precipitation. If the difference was greater than the storm threshold, the county was determined to be at higher risk for that decade. For storms, increased risk was determined if the average projected number of storms per year was greater than the historical baseline. Researchers also used datasets from the California Department of Education (CDE) to determine the number of counties, districts, schools, and students impacted. Note data is from 2022-23 and does not take into account growth in student population between 2025 and 2055.