California Drenched by Pineapple Express

Allison Bodaken

Staff Writer 

After an unusually dry January, California is now facing an onslaught of torrential rain and heavy snowfall. This atmospheric event is delivering vast amounts of moisture to the region, raising concerns over flooding, landslides, and travel disruptions. Meanwhile, the heavy precipitation offers both relief and risk in the aftermath of recent wildfires in Southern California.

The weather pattern, known as a Pineapple Express, is set up by low pressure situated to the northeast of Hawaii, which propels moist tropical air from Hawaii and across the Pacific Ocean. The Guardian explains that the result is a stream of heavy precipitation piling into parts of the west coast of the U.S., falling as snow down to about 4,000 feet with rain at lower levels. A cumulative total of 24.4 inches of rain has already hit some areas, while up to six feet of snow will be possible in mountainous areas, reports CNN.

While atmospheric rivers like the Pineapple Express play a crucial role in replenishing California’s water supply, their intensity can cause catastrophic damage. These systems have been responsible for some of the most severe flooding events in the state’s history, leading to mudslides and infrastructure damage, explains BBC. 

More than half a million Californians are without power due to wind damage. In another article, CNN reports that some residents in Santa Barbara, San Jose, and Los Angeles have been instructed to evacuate. Closer to Malibu, schools have closed for the week, stating on X, formerly known as Twitter, that due to road closures, many staff members were unable to get to campus. And in Bel-Air, communities received upwards of 11 inches of rainfall. “Due to the hilly nature of our canyons, there are multiple mudslides and landslides, and tons of debris in our roads. Many of the roads are closed,” Bel-Air Association spokesperson Hattie Rogovin told CNN.

In the north, the Pineapple Express has unleashed extreme rainfall, says a second BBC article. Cities such as Redding, Chico, and the San Francisco Bay Area have already experienced significant downpours, leading to rising water levels and road closures.

CNN reports that San Francisco, for example, received 2.53 inches of rainfall in one day—breaking a record set in 1887—while areas in the northern Sierra Nevada have seen as much as 32 inches of snow. CNN warns some areas above 7,000 feet could receive between three to six feet of snow, creating hazardous travel conditions and increasing avalanche risks. 

These excessive amounts have heightened the threat of flash flooding and mudslides, says AccuWeather, especially in regions recently scorched by wildfires. The National Weather Service has issued warnings for possible flash floods in areas where recent wildfires have stripped the land of vegetation, reducing its ability to absorb moisture. 

The weather was expected to subside during the second week of February, but its impact lingers. Floodwater may take days to recede, and snow accumulation in the Sierra Nevada will continue to influence river levels as it melts in the coming months. 

The unpredictability of these events poses an ongoing challenge. The Associated Press warns that more damage is possible this year. As global temperatures rise, atmospheric rivers could become more intense, increasing the risk of both prolonged droughts and extreme flooding. This coupled with the lasting effects of El Niño will lead to some of the highest tides of the season.

In California’s future, water levels might get even more difficult to manage. Upwards of 75 percent of Californians get their drinking water from the Sierra Nevada snows. According to the U.S. National Oceanic and Atmospheric Association (NOAA), by 2100, climate change will have caused a significant decrease in rainfall and snowfall in the mountains. 

Image courtesy of Getty Images.