Atmospheric river explained

Empty parking lot post-rain at sunset (Josie Eubank, The Puma Prensa)

By Advait Sathe, staff writer

Santa Rosa, along with most of the Bay area, has experienced an uncommon drenching over the past few months, leading to Maria Carrillo High School students bundling up and sheltering under umbrellas. Wondering why? Most of the rain has been caused by atmospheric rivers, a weather phenomenon that can stretch across hundreds of miles of land.  Atmospheric rivers are long, narrow streams of moisture-laden air that flow through the atmosphere. These rivers, which can extend for thousands of miles, carry enormous amounts of water vapor from the tropics to other regions o f the globe, including California. When an atmospheric river makes landfall in California, it can bring torrential rainfall, strong winds, and severe flooding. The impact of atmospheric rivers on the state's population and infrastructure can be significant, causing widespread damage and disruption.

In California, atmospheric rivers are a frequent occurrence during the winter months, especially along the state's coast. These rivers of moisture, sometimes referred to as "Pineapple Express" storms, originate in the warm waters of the Pacific Ocean near Hawaii and then travel eastward toward the California coast. 

In addition to flooding, atmospheric rivers can cause landslides and mudslides. California's steep coastal mountains are prone to landslides, especially during heavy rainfall. When an atmospheric river hits, the moisture-laden soil can become unstable, causing hillsides to collapse and debris to flow downhill. Landslides can damage homes, block roads, and pose a significant risk to human life. If hillsides have been recently affected by wildfires, the lack of plant roots to hold the hillside down increases the risk presented by landslides. 

There are some upsides to atmospheric rivers, though, as they help refill lakes and reservoirs after the massive drought that California has been experiencing. Already, many experts are saying that the recent atmospheric rivers have been massively effective in pulling California out of a drought. 

Atmospheric rivers are a significant threat to California residents, bringing much-needed precipitation to the state's water supply but also causing severe flooding, landslides, and damage to infrastructure. Time will tell whether they ultimately aid or wreak havoc on the local economy