A magnitude 5.1 earthquake struck Southern California on Sunday in the area of Tropical Storm Hilary. The quake struck about 4.3 miles southeast of Ojai in Ventura County. The Geological Survey warned residents of the area to be prepared for possible aftershocks. Some subsequent earthquakes of magnitude 3 or higher have already been recorded.

The Ojai earthquake, about 130 miles northwest of Los Angeles, occurred at the same time as Tropical Storm Hilary hit Southern California. The storm hit land Sunday afternoon on Mexico's northwestern Baja California peninsula as authorities warned of dangerous flooding in the area and across the American Southwest.

Emergency in California and Nevada

In recent hours, Nevada Governor Joe Lombardo declared a state of emergency for Tropical Storm Hilary. Current forecast models predict severe weather throughout the state of Nevada.

In California, Gov. Gavin Newsom also declared a state of emergency across much of the southern part of the state amid the forecast of "catastrophic and life-threatening flooding."

Hurricane Hilary formed in the eastern Pacific Ocean and was initially declared a Category 4 storm. Hilary made landfall in California late Sunday when its maximum winds dropped from 110 miles per hour to about 40, making it a tropical storm. The National Hurricane Center forecasts that it will cross parts of Southern California and Southern Nevada on Monday. Meanwhile, there are warnings for flash floods in affected areas, and flights continue to be canceled as a result of weather conditions.