A major weather event is set to hit the West Coast this week as a massive atmospheric river, known as the 'Pineapple Express', is expected to bring torrential rain and potential flooding. Originating near Hawaii, this system is notorious for delivering substantial moisture to the west coast, with significant rainfall anticipated in California and the Pacific Northwest. The National Weather Service (NWS) has issued flood warnings for the Seattle/Tacoma area as temperatures up to 63 degrees Fahrenheit (17C) are forecasted over the next two days.

The latest atmospheric river is also what you'd call a "Pineapple Express." Moisture builds around Hawaii & streams toward the west coast. 🌊

As the system moves east, rain will begin to spread down along the coast & into California Wednesday. 💦#cawx pic.twitter.com/xVmGLyKwhi

— Veronica Dolan (@DolanWx) January 30, 2024

Oregon is also expected to face heavy rainfall until Wednesday, posing a risk of mudslides as the rain saturates the soil. By Tuesday evening, the 'Pineapple Express' is predicted to move southward to California, with up to eight inches of rain expected in parts of northern California, leading to flooding across the region from late Wednesday into Thursday. The Bay Area and Los Angeles are preparing for significant rainfall as well, with areas of higher elevation, like the Sierra Nevada mountains, experiencing small amounts of snow.

The 'Pineapple Express' is characterized as an atmospheric river, which transports a concentrated stream of moisture from the tropics toward the West Coast. When this moisture hits the coast, it has the potential to produce heavy rainfall, snowfall, flooding, mudslides, and landslides, depending on the temperature and terrain. Last winter, California experienced the longest stretch of continuous atmospheric river conditions in the past 70 years, leading to widespread flooding and snow accumulation in the Sierra.

This season, the west coast has experienced below-average precipitation, but the approaching 'Pineapple Express' is expected to bring a significant amount of precipitation, potentially increasing the snowpack in the Sierra. The implications of the 'Pineapple Express' are twofold - while it can replenish water supplies, moderate temperatures and provide essential resources for agriculture and power, it can also cause flash floods, mudslides, road closures, power outages, and damage to property and infrastructure, raising concerns about its potential impact on the region.

This weather event follows several weeks of extreme winter weather across the United States, with heavy snow, brutal cold, and devastating ice storms hitting northern states. In particular, the Pacific Northwest faced a devastating ice storm earlier this month, resulting in multiple fatalities and widespread damage. As the 'Pineapple Express' approaches, residents and authorities are preparing for the potential impacts of this significant weather system. Stay updated with the latest weather alerts and take necessary precautions to ensure safety.