55 - Climate Change and Mosquito Control: The Effect of Atmospheric River Events in California’s Central Valley

Abstract: Atmospheric rivers (ARs) are a type of storm that produce 50 percent of California’s water supply and are responsible for 90 percent of the state’s floods.  As the name implies, they are like rivers in the sky.  These elongated plumes of moisture carry saturated air from the tropics to higher latitudes and deliver large amounts of precipitation in the form of either rain or snow.  In the winter of 2023, California experienced 12 of these extreme weather events which led to extensive flooding in areas that have become accustomed to severe drought.   In March of 2023, both State and Federal Disaster Declarations were executed to assist communities impacted by flooding, snow, mudslides, avalanches, and debris flows that resulted from storms.  Over roughly 3 weeks some parts of the state received 2-3 feet of rain and many communities struggled with flooding as water was diverted away from “towns” and into the once dry Tulare Lake basin which was previously recognized as the largest body of fresh water west of the Mississippi.   The sudden reappearance of Tulare Lake, which was drained for farmland in the late 1800s, caused hundreds of millions of dollars in agricultural losses and the emergence of mosquitoes in unprecedented numbers.  With assistance from the California Department of Public Health (CDPH), Vector Disease Control International (VDCI) was called in to assist vector control agencies in Tulare and Kings counties with aerial larval and adult mosquito control operations.  This presentation will cover the logistics involved with emergency response, touch on climate change, and highlight the importance of collaboration when dealing with unprecedented mosquito control issues.