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Thousands of landslides have occurred in California due to active tectonics, weak earthen materials, and high seasonal precipitation. On July 8, 2023, a landslide damaged more than 12 homes and caused millions of dollars in damage in Rolling Hills Estates located on the Palos Verdes peninsula in Los Angeles, California. The landslide occurred during a dry period (more than 40 days without rainfall) that followed an unusually wet winter (2022-2023 rainfall rate 0.6 m/yr; 30-year average rainfall rate 0.32 m/yr). We used satellite-based synthetic aperture radar interferometry (InSAR) time series on Copernicus Sentinel-1 data acquired between January 2020 and July 2023 to measure the deformation history of the landslide. We found that the Rolling Hills Estates landslide was stable but began moving slowly at rates of around 0.5 cm/month for more than three months before it accelerated rapidly and collapsed. We …