Heavy rains in California: What are the ‘rivers in the sky’, a phenomenon that threatens to flood the state?

California will receive more rain and flooding starting Saturday night and extending into early next week, as another powerful atmospheric river arrives from the Pacific Ocean.

Los Angeles is likely to receive 5 to 6 inches of rain, while Santa Barbara will receive up to 16 and the mountains and hills along the coast could get 10 inches or more, said Marc Chenard of the Weather Prediction Centerfrom the United States. This comes on the heels of a system that already caused flooding from San Francisco to Southern California.

“It looks like it will be a major event and will last longer than the past,” Chenard said by phone. “The fact that it is later in the year, on top of what has been a wet period, surely makes everything worse.”

With streams and rivers already overflowing and the ground saturated, andFlood risk throughout Central and Southern California is high. Additionally, landslides are likely, and with strong winds, the chances of power outages increase.

California has already seen widespread flooding scenes in San Diego last month and across the state this week.

How do rains affect rivers?

Los Angeles International Airport received 6 centimeters on Thursday. The Los Angeles River near Wardlow Road has risen about 32 inches since Thursday, the National Weather Service said.

Looking ahead, the Santa Clara River near the town of Piru will rise 2.27 feet on Monday. Both will remain well below flood stage. Meanwhile, in coastal areas of Orange County, waves are forecast to reach 10 feet.

“Stream flow is well above average, base conditions are well above average,” Chenard said. This means that the danger of flooding has an advantage.

In addition to the rain, heavy snowfall in Sierra Nevada at 5 thousand feet or more until early next week. Up to 24 inches of snow is possible with possible rates of 1 to 5 centimeters per hour, the National Weather Service said.

A year ago, a series of atmospheric rivers (long plumes of moisture off the Pacific) killed at least 22 people and caused $4.6 billion in loss and damage, according to the National Centers for Environmental Information.

What is a river in the sky?

According to the National Oceanic and Atmospheric Administration, of the United States Department of Commerce, a river in the sky are regions relatively long and narrow sections of the atmosphere, which transport most of the water vapor away from the tropics.

While atmospheric rivers can vary greatly in size and strength, the average carries an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River.

Rivers with an exceptionally strong atmosphere can carry up to 15 times that amount. When atmospheric rivers make landfall, they typically release this water vapor as rain or snow.

Although atmospheric rivers come in many shapes and sizes, those that contain the largest amounts of water vapor and stronger winds can generate rain and extreme flooding, often by ponding in flood-vulnerable basins.

With information from Bloomberg.