A powerful atmospheric river storm is poised to unleash heavy rain, widespread flooding, and significant snowfall across California during the holiday week, threatening to disrupt Christmas plans and travel. This Pineapple Express system, expected to intensify from Tuesday through Thursday, has prompted the National Weather Service to issue Flood Watches and various alerts for much of the state through Friday.
The storm will deliver copious moisture, with Northern California’s Sierra and foothills bearing the brunt. Forecasts indicate that locations like Blue Canyon could receive up to 14 additional inches of rain, while Placerville and similar areas may see 10 inches. In the valleys, including Sacramento and San Joaquin, rainfall is expected to be lighter at 2 to 3 inches, but still sufficient to cause ponding on roads and minor river flooding, particularly along the Sacramento and Cosumnes Rivers.
Southern California is not spared, with models predicting 4 to 8 inches of rain in coastal and valley areas, and up to 12 inches in the mountains. There’s an 80% chance that downtown Los Angeles will get 2 or more inches, potentially making this one of the stormiest Christmases since 1971. The heaviest downpours, with rates of half an inch to 1 inch per hour, could trigger flash flooding, mudslides, and debris flows, especially in regions with recent wildfire scars.
Snow accumulation will be substantial in the Sierra Nevada, where several feet of powder are forecasted. Starting Wednesday, snow levels may drop to 6,000 feet, with Donner Summit expecting 2 to 4 feet and Sonora Pass up to 6 feet. This will likely lead to travel delays, chain controls, and possible closures on key mountain routes, complicating holiday journeys.
Strong winds are another major hazard, with gusts potentially reaching 50 to 60 mph in exposed areas. These winds could topple trees and power lines, causing scattered outages and increasing the risk of accidents. The National Weather Service advises residents to secure loose outdoor items and avoid parking under tall trees.
In preparation, Governor Gavin Newsom has mobilized emergency response teams and equipment to nine counties, including El Dorado, Orange, and Marin, to enhance flood protection and response capabilities. This proactive measure aims to mitigate the storm’s impact on communities and infrastructure.
The timing coincides with peak holiday travel, raising concerns for safety and convenience. Officials recommend avoiding non-essential travel, particularly in mountain regions, and staying updated via local news and weather apps. Travelers should expect delays and plan for alternative routes if necessary.
Looking ahead, this event underscores the increasing volatility of California’s weather patterns, driven by climate change. Residents are urged to prepare emergency kits, heed official warnings, and report hazards promptly. While the storm may bring much-needed snowpack for water resources, its immediate effects demand vigilance and caution throughout the holiday season.
