“Tropical storm Hilary, having weakened from a Category 1 hurricane, is speeding up while pushing into Southern California Aug. 20, prompting evacuation warnings and cancellation of flights, classes, and sports games in some regions, bringing a stretch of rainfall expected to last through Monday.

Residents are asked to remain indoors as the tropical storm will likely bring “catastrophic and life-threatening” flooding to the region, according to National Weather Services (NWS).

The NWS has issued Southern California’s first-ever tropical storm watch Friday night—encompassing Los Angeles County, Orange County’s coastal and inland regions, and the Santa Ana Mountains and foothills. The state has not experienced a tropical storm landfall since 1939.”