In California, precipitation replenishes water supplies but increasingly occurs as intense storms, causing floods, landslides, and erosion that threaten ecosystems, communities, and infrastructure, requiring comprehensive mitigation efforts.
Core Question: What are the projected climate impacts for each county in California in the next three to four decades?
Additional Questions:
Which climate impacts have the greatest threat to the core functions of TK-12 schools, and what does the data show for how these impacts will affect each county region?
How are these climate impacts impacting the following aspects of school: school infrastructure and resources, the physical and mental health of students and employees, and the ability to learn and play safely and without ongoing climate-related disruptions?
This video provides an overview of how to utilize the Tableau Interactive Maps below to view the projected climate impacts over time. It includes how to use the filters and tools within the visualizations to see how the impacts will change in each county for date ranges starting in 2020 and spanning to 2059. Written instructions can also be found in each section.
Video: How to Use Data Interactives
Data Indicator Definitions
An extreme weather event is an occurrence that is significantly different from typical weather at a specific location and time of year. Extreme precipitation events can lead to flooding, mudslides and other damaging events. In a changing climate the intensity and frequency of such events will likely change across California. This tool visualizes how climate models predict extreme precipitation events will change over the 21st century.
Daily climate projections for California at a resolution of 1/16° (about 6 km, or 3.7 miles) generated to support climate change impact studies for California’s Fourth Climate Change Assessment. The data, derived from 32 coarse-resolution (~100 km) global climate models from the CMIP5 archive, were bias corrected and downscaled using the Localized Constructed Analogues (LOCA) statistical method. The data cover 1950-2005 for the historical period and 2006-2100 (some models stop in 2099) for two future climate projections. Details are described in Pierce et al., 2018. It should noted that precipitation data could not provide discrete decadal data. Rather, it only listed a prediction for 2050; therefore precipitation data is extrapolated based on the prediction for 2050.
Data Sources
The visualization (left) shows the difference in rainfall (in inches) from the Modeled Baseline and the forecasts between 2020 and 2059.
Regions with an average of 10 inches less than the baseline are show in in tan. Regions with an average of 10 inches more than baseline are shown in dark blue.
Use the dropdown to the right of the map to select the date range.
Hover over or click on each county to view the specific data for that county.
Overall, we can see that the average amount of rainfall does change somewhat over time, but there is not a linear trend towards more or less rain.
The visualization below shows landslide risk. The dark brown colors express the counties of higher risk of landslide based on the FEMA Risk Index. In the National Risk Index, a Landslide Risk Index score and rating represent a community's relative risk for Landslides when compared to the rest of the United States
.The visualization below shows riverine folloding risk. The dark blue colors express the counties of higher risk based on the FEMA Risk Index. Riverine Flooding is when streams and rivers exceed the capacity of their natural or constructed channels to accommodate water flow and water overflows the banks, spilling out into adjacent low-lying, dry land.
School campuses contain a significant amount of impervious landscape, such as paved playgrounds, parking lots, plazas, and corridors. These smooth, open surfaces are essential for safety and practicability when it comes to navigating campus and in certain emergencies. However, as California’s school communities have begun experiencing extreme precipitation and storm based flooding as an impact of climate change they are now experiencing new emergency concerns. From a surface water perspective, all that asphalt and paving can lead to significant runoff when it rains, in particular when there is heavy rain (sometimes referred to as atmospheric rivers or severe storms).
This storm based flooding can have multiple effects on schools, for example:
High winds and heavy rain can affect the power supply and electrical systems;
Flooding can have lasting effects on buildings such as water damage, mold, wood damage due to water, metal corrosion, distortion on walls and floors, water contamination, and the damage of other school supplies such as furniture, computers, files, books, and food;
Flooding can also impact school grounds, where severe wet weather can and poorly draining adjacent roadways can cause delays or even full impediment to accessing school entrances, and ponding onsite can cause disruptions or even safety hazards for students, families and staff;
Landslides due to heavy rains, especially following a wildfire, can cause direct damage to buildings or roads, potentially cutting students off from school or increasing commute time; and,
During longer periods of drought following warmer and wetter winters, schools can succumb to the impacts of extreme heat and increased pressure on water supplies.
Because storm drain systems are often a separate network of gutters, pipes, and other drainage features that ultimately connect to creeks, rivers, and then bays and oceans without any treatment, schools can end up contributing to broader stormwater management challenges. For example, extra runoff flowing from schools can also add to localized flooding and creek erosion during big storms, and the issue of trash in storm drains can be exacerbated when haphazardly discarded straws, plastic baggies, and other single-use items from school sites are flushed into the storm system.
It is also important to note that many families will be highly impacted by flooding and storm damage in their own homes, and that historically marginalized sub groups within the school community may be impacted more severely than higher income families in the community or impacted more dramatically than the school itself. This may also contribute to disruptions to learning for some students.
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.
Learn more about how Flooding will Affect Schools in this 2020 Hechinger Report Article.
Summary of Data Analysis on Extreme Precipitation and Storms: This is not an easy thing to forecast, and the forecast is not linear. We cannot necessarily say this is a problem at this specific time, or this is a problem and everyone will experience water falling from the sky in the same way. School districts need to understand the environment and topographically where they are situated and what it means to have rain and storms. Everyone is going to experience this in one way or the other, and understanding what type of biome you are in, and the changes decade to decade are important.
It is recommended to consider all of the Readiness and Emergency Management for Schools (REMS) phases of emergency planning for each impact:
Prevent (Mitigate): This prevention (or mitigation) phase involves taking actions to reduce or eliminate risks and hazards before they happen.
Preparedness: The preparedness phase involves developing plans and procedures to ensure schools are ready to respond to emergencies.
Respond: The response phase takes place during an actual emergency, when schools take immediate action to protect students, staff, and visitors.
Recovery: The recovery phase happens after the immediate emergency is over, and is focused on restoring the physical environment, and supporting students, families, and employees to return to learning routines as soon as possible.
Stormwater Flooding Mitigation/Prevention Examples:
Generally infrastructure solutions to stormwater management will include methods that either capture on site or slow and filter stormwater into groundwater systems. Examples include the following:
Slow and Filter: Schools can restore wetland habitats, invest in green infrastructure, or rain gardens ranging from small to large scale projects that naturally absorb water during a heavy storm and mitigate the effects of flooding.
Capture: Rainwater catchment systems can similarly by small or large in scale, depending on the severity of potential flooding risks to facilities. Small scale examples include adding rainwater catchment systems to existing drain systems. Large scale schools can install regional stormwater capture systems.
The San Carlos School District partnered with their local stormwater management county agency partner Flows to Bay to mitigate and prepare for storm-based flooding. Learn more about what they are doing by reading the Spotlight Feature from September 2024: Stormwater Management in San Carlos School District.
Santa Barbara Unified School District (SBUSD) and the Yolo County Office of Education are taking steps to mitigate the impacts of extreme weather on their ability to access energy by implementing a microgrid system. Learn more about what these LEAs are doing by checking out the May 2024 Open Door Webinar on Energy Resilience, and the June 2024 Spotlight feature on UC Santa Barbara’s Microgrid System.
In February of 2024, San Diego schools experienced what was once considered once-in-a-generation precipitation and flooding, testing the emergency services response protocols at the San Diego County Office of Education and encouraging them to think about long-term prevention and preparedness. Listen to their story from the Open Door Webinar, Preparing for a New Normal: Climate Emergencies and Their Impact on Schools - San Diego COE (20:17 - 30:29)
