Abridged version:
- The National Weather Service office in Sacramento expects widespread rain beginning Friday morning, with more possible through early next week.
- Expect gusty winds and mountain snow. Wind gusts could reach 45 mph in parts of the valley and the Sierra could receive up to 2 feet of snow at high elevations.
- El Niño doesn’t guarantee a wet winter. Northern California has experienced wet, average and dry winters during previous strong El Niño events. Forecasters currently see a 40% to 60% chance of above-normal precipitation this winter.
Sacramento is heading into a wet weekend as a series of storms bring rain, gusty winds and mountain snow to Northern California, with more rain possible into next week.
The storms are arriving as forecasters anticipate a strong El Niño winter. Though El Niño increases the likelihood of wetter conditions in parts of the state, previous years show that Northern California doesn’t always follow that pattern.
Former KCRA Chief Meteorologist Mark Finan said there will be three main waves of storms: Friday, Sunday night into Monday and another round expected Wednesday. The weekend is expected to be mostly dry during the day, with relatively tame storms bringing much needed rain to the valley and snow to the Sierra, without much flooding.
Sign Up for the Morning Newsletter
The Abridged morning newsletter lands in your inbox every weekday morning with the latest news from the Sacramento region.
What to expect
- Friday: ¼ to ⅓ inch of rain in Sacramento
- Saturday: mostly dry during the day
- Sunday: mostly dry during the day, second wave comes in the evening and can bring up to an inch of rain come Monday.
- Monday: prolonged rainfall most of the day
Rain is expected to move into the Sacramento region Friday, with potentially heavy rain and thunderstorms in the afternoon and evening. Gusty winds are also possible, and wind advisories are in effect for portions of the valley.
The first storm isn’t expected to bring an atmospheric river, which typically means more prolonged rainfall, Finan said. Much of the moisture will move through relatively quickly.
Conditions should start to clear on Saturday, with much of the day and Sunday expected to stay dry. Finan said the next significant round of rain will likely arrive Sunday night and continue into Monday morning. That storm system, along with the storm expected Wednesday, has a better chance of bringing atmospheric river conditions.
“When you see Monday that it can rain for six to 10 hours or so, then that’s kind of more the feature of an atmospheric river that you tend to see more prolonged rain,” Finan said.
Snowstorm in the mountains
Ski resorts will benefit from the incoming snow, Finan said. Drivers heading into the mountains should be prepared for chain requirements, especially by late Friday afternoon or evening.
Sierra-at-Tahoe Ski Resort is anticipating its biggest snowstorm of the fall, with up to 21 inches over the next five days, according to Sarah Sherman, director of sales and marketing. The storm is arriving at a typical time for the resort as it prepares for its winter opening, usually in late November or early December.
“This snowfall is really aligning with what we’d hoped to expect as we prepare to open,” Sherman said. “This one is kind of right on par of when we hope to see that really stick around for winter.”
Sherman said the resort has been working around the clock all summer to prepare for winter, including maintenance on the chairlift, clearing trails and removing obstacles. Sherman waits to count snow until it’s on the ground, though it could arrive as early as Friday afternoon. The resort will open once snow accumulates enough to build a strong base layer.
Residents should keep an eye on updated forecasts and alerts, watch for flooding and unsafe road conditions and prepare for strong winds that could cause power outages. Sherman advises people coming up the mountain to check the resort’s snow report ahead of time.
Sacramento County has opened three sandbag locations ahead of the storms to help residents prepare for possible flooding. Sand and bags are free, but bring a shovel. Now is also a good time to clear gutters and drains of leaves and debris. More storm preparation tips can be found on the Sacramento County website.
“These are nice little systems that will be beneficial in terms of water, certainly ending the fire season in Northern California and then starting the snowpack as well,” Finan said.
Comparing past El Niño winters
California has experienced several notably strong El Niño winters, but their effects have varied. The 1982-83 and 1997-98 winters were especially wet, and Sacramento recorded about 167% of its normal water-year rainfall in 1977-98. But the 2015-16 winter showed that a strong El Niño doesn’t guarantee more rain. Despite being one of the strongest events on record, Sacramento received about 88% of its normal rainfall that year.
Of the six very strong El Niño events since 1950, Sacramento experienced two wet winters, two near-normal winters and two dry winters, according to the National Weather Service. The incoming amount of rain and snow this weekend looks normal for early-to-mid November, Finan said.
The U.S. Army Corps of Engineers works year-round to reduce flood risk throughout the region by building, strengthening and maintaining flood control infrastructure such as levees, bypasses and weirs. Lt. Col. Kara Greene said there’s been substantial investments in flood risk reduction since the region experienced major floods in 1986 and 1997.
“The system today is stronger because of those improvements, but we’re continuing that work today,” Greene said. “The main point is to prevent water from going under, through or over a levee from one of Sacramento’s rivers.”
Improvements continue to come to Sacramento’s flood infrastructure. Greene said Sacramento’s existing weir requires a person to physically pull a chain to open its gates during high water events, allowing water to enter the Yolo Bypass. A new weir being built will operate automatically. State agencies like the Department of Water Resources currently operate the mechanisms.
What El Niño means for the rest of winter
The National Weather Service office in Sacramento’s El Niño update from October gave an 83% chance that the developing El Niño would become a historically strong event, potentially exceeding previous events dating back to 1950. The Climate Prediction Center also projected a 40% to 60% probability of above-normal precipitation across Northern California for the season, with the chances higher during January, February and March.
Finan said we can’t attribute storms to being caused by El Niño, rather its influence on the region is better understood by looking at the entire rainy season after it ends.
Storm activity could pick up later in the winter after a slower start. Sacramento can benefit from an atmospheric river’s rain and Sierra snow, but multiple storms arriving close together can increase runoff and pressure on flood-control systems.
“It takes quite a while for the ground to become saturated and for us to start worrying about streams and creeks and that sort of thing,” Finan said.
