Wednesday January 4, 2023
NASA Earth Observatory —
Heavy rain hit parts of central and northern California on New Year’s Eve 2022, flooding communities near San Francisco and Sacramento. Water breached levees along the Cosumnes River near Wilton, California, flooding numerous roads including Highway 99—a major thoroughfare in the Central Valley. Wilton and other nearby farming communities were issued evacuation orders.
The Bay Area National Weather Service measured 5.5 inches (14 centimeters) of rain in downtown San Francisco on December 31, 2022, the second wettest day in more than 170 years of record-keeping. This daily total is about half of the city’s expected rainfall for the entire month of December. Toward the northeast in Sacramento County, some areas recorded up to 4 inches (10 centimeters) of rain within 24 hours, according to the National Weather Service.
The flooding that ensued is visible in the false-color image (right) acquired on January 1, 2023, with the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. Water appears light to dark blue. Vegetation is green and bare land is brown. For comparison, the MODIS image from December 16, 2022 (left) shows the same area prior to the intense rainfall.