500+ mm of rain possible in California as next atmospheric rivers arrive
The next Pineapple Express heading for the West Coast will miss British Columbia and drench California with flooding rains
Recent atmospheric rivers have brought widespread flooding to British Columbia as persistent waves of heavy rain washed over the region.
The next potent atmospheric rivers aiming for the West Coast will remain south of the border, and they're on track to produce some serious rainfall totals.
DON’T MISS: What’s a Pineapple Express? Diving into this robust atmospheric river
Active storm track continues for the West Coast
A strong jet stream has brought wave after wave of storms and heavy rain to southwestern B.C. in recent weeks, culminating in widespread flooding throughout the Fraser River and Sumas River valleys.
While forecasters still expect plenty of low-elevation rain and mountain snow across southern B.C. through this weekend and into next week, the most active weather will finally shunt across the international border as the jet stream dips farther south.
Flooding rains eyeing California into next week
Over the next week, a series of low-pressure systems will funnel into the California coast a potent type of atmospheric river known as a Pineapple Express.
This rich plume of moisture travelling straight from the Hawaiian Islands will allow abundant heavy rain to engulf the northern half of California into next week.
MUST SEE: Tule Fog can blanket California in a thick cloud for days
Rain is expected high into the Sierra Nevada, where enhanced lift may help produce more than 500 mm of rain in some regions. Flooding, mudslides, and rockslides are likely as heavy rain drenches the region.
Lower elevations are also expecting some hefty totals.
Sacramento’s forecast of up to 175 mm of rain would equal about 40 per cent of the city’s total annual average precipitation. San Francisco could see an entire December’s worth of rain in just a few days.
Drenching rains like this are a critical part of the water cycle in this region of the world, as they replenish area waterways to get through the dry months. However, snow at higher elevations would be ideal for banking water resources ahead of the next wildfire season.
The good news is that the entire state of California found itself free of drought this month, for the first time since July 2024.