Emergency has been declared in California over risks of disastrous flood as a result of storm.

Officials in Southern California are alerting locals to the possibility of "life-threatening and damaging flooding" as a storm system powered by a gigantic air river brings deadly waves and heavy, prolonged rains beginning on Sunday.

This storm has the potential to produce more than twice as much rain as Thursday's, which resulted in major flooding, regional traffic closures, and water rescue operations, according to the Los Angeles Times.

"This is a potentially dangerous situation, and we are urging everyone to be preparing in advance," Ariel Cohen, a National Weather Service meteorologist, said Friday. This includes setting up sandbags, modifying travel schedules for cars, having several ways to get weather alerts, and being ready to flee, particularly for residents of low-lying locations.

Cohen issued a warning that "all areas will be susceptible to life-threatening, damaging flooding" throughout the counties of Santa Barbara, Ventura, and Los Angeles, despite considerable uncertainty regarding the storm's direction and speed. Authorities issued a warning of mudslides, toppled trees, power outages, and even avalanches due to the forecast high winds and heavy snowfall.

A "rare amount of rain" is expected to fall on the area, with most of it falling in a 24-hour period, according to agency meteorologist Ryan Kittell. Over 5 inches are predicted for downtown Los Angeles between Sunday and Tuesday, over 7 inches for Pasadena, 9 inches for Ojai, and 6 inches for Westlake.

“We just got a taste of it with this last storm, where there was some significant flooding in Long Beach," Kittell said, "but we’re expecting much more rain than that, and in a widespread area."

Communities around the state are bracing for intense rain through Tuesday, with 94% of the population, or an estimated 37 million people, at risk of flooding, according to an AccuWeather analysis that looked at places that were already drenched and were predicted to receive two or more inches of rain.