Strong Storm Will Bring High Winds, Heavy Rain, Feet of Sierra Snow to California Through Saturday

Linda Lam
Published: April 7,2017
A powerful spring storm system continues to move into the West, bringing significant weather to parts of California and the Pacific Northwest.
This incoming system comes toward the end of the state's wet season, which has delivered near-record precipitation.
(MORE: Where Winter 2016-17 Ranked)
Friday morning, wind damage was reported in northern California and Oregon. Damage to a roof was reported in San Leandro, California and power lines came down near Lafayette, where homes were also threatened by a nearby landslide. A widespread power outage was reported in Crescent City. A wind gust of 76 mph was recorded at Mount Diablo and the Oakland Airport reported a gust of 62 mph.
Power outages continued into Friday afternoon in Crescent City following gusts as high as 71 mph.
(MORE: West Coast Storm Latest Impacts)
In Oregon, Interstate 5 was closed in both directions north of Albany due to downed power lines across the highway. Numerous reports of downed trees were received Friday in western Oregon, including the Portland area where a wind gust of 53 mph was measured. Mount Hood recorded a gust of 86 mph early Friday morning and a gust of 90 mph was measured near Harlan, Oregon. In eastern Oregon, winds climbed to around 60 mph during the afternoon.
An upper-level trough and a strong area of low pressure, especially for April, will continue to push onshore, spreading rain, higher-elevation snow and gusty winds across the region.

Current Satellite, Pressure and Moisture

This storm may be able to tap deeper sub-tropical moisture, resulting in moderate to heavy precipitation. A few thunderstorms are also possible Saturday in parts of Utah.
(MAPS: Weekly Planner)
High wind warnings and wind advisories have been posted for portions of northern California for wind gusts up to 65 mph, as well as for parts of Nevada, Oregon, Washington, western Utah, northern Arizona and western Colorado.
Winter storm warnings have also been issued for the higher elevations of the Sierra and Wyoming's Tetons and Wind River Range, where heavy snow is likely.

Current Conditions and Radar

Rain and snow will spread across the region as this potent low-pressure system moves onshore.

Forecast Details

Saturday

• Rain and snow will persist into Saturday for much of the West, before ending in most areas by Saturday night.
• Showers will spread eastward into northern and central Rockies by late in the day, and turn to snow in higher elevations. 
• Winds will decrease through the day, as well.
• FORECAST: Los Angeles | Redding, California | Seattle

Saturday's Forecast

How Much Rain and Snow Is Expected?

Snowfall will likely be measured in feet in the higher elevations of the Sierra, with some areas likely adding up to 4 feet of snow to the already hefty snowpack. Colder temperatures may allow snow to fall at elevations as low as Lake Tahoe by Saturday, although in the southern Sierra heavy snow will generally fall above 7,000 feet.
Through Friday morning, Northstar Ski Resort reported 13.0 inches of snow and Squaw Valley reported 12.0 inches.
This combination of heavy snow and gusty winds will make for hazardous travel.

Additional Rain and Snow Forecast

Much of northern California, as well as parts of central California, will receive 1 to 3 inches of rain through Saturday. Some areas along the coasts of northwestern California, as well as the foothills of the Sierra, could see up to 3 inches of additional rainfall.
(MORE: Where March and April Are the Snowiest Months)
In some areas, precipitation from this system may exceed the average monthly precipitation for April. Sacramento usually receives about 1.15 inches of rain in April, and from Thursday through Saturday the current forecast is for close to 1.50 inches. In fact, 1.11 inches fell on Thursday in Sacramento.
According to the National Weather Service office in Reno, Nevada, the last time Tahoe City saw a two-day total of at least 2 inches of liquid precipitation in April was in 2003, and more than 2 inches in currently anticipated.

Flooding Concerns?

The ground in many areas is already saturated from the above-average precipitation that occurred this winter, and many rivers are already running high. Flood watches have been posted for portions of California and western Nevada.
Some roadway flooding was reported Friday morning, including near Santa Rose, California and Fairfield, California.
Oct. 1 to March 31 was the wettest on record in Sacramento, Reno and South Lake Tahoe, according to the Southeast Regional Climate Center. In the Pacific Northwest, this six-month period was also the wettest in Spokane, Washington; Pocatello, Idaho; Lewiston, Idaho; Kalispell, Montana; and Sheridan, Wyoming.
Typically, when April rolls around, the chance of big storms bringing heavy rain and snow decreases in California. Given the wet water year, it is no surprise that another strong storm system is poised to bring another round of precipitation through early April.
The water content in the snowpack throughout much of the West remains well-above average. As of April 4, areas of the Sierra and western Nevada are more than 200 percent of average for the date, according to the Natural Resources Conservation Service SNOTEL network.
When examining the snow-water content for the northern, central and southern Sierra, all areas are at least 145 percent to average for April 4, according to the California Cooperative Snow Surveys.
This year's snowpack is quite a change from the past few years, when drought prevailed across California.
When the upcoming heavy rainfall is combined with any snowmelt that takes place, courtesy of the recent warmer temperatures, and the saturated ground, this early April storm could result in flooding in some areas, especially for lower-elevation creeks and streams.
The saturated ground will add to the risk for landslides and rockslides in some spots, as well.
An extensive mud and debris flowed into state route 153 near Pateros, Washington on Friday morning.
In addition, many reservoirs continue to run above average, including Lake Oroville, Lake Shasta, Sun Luis Reservoir and Pyramid Lake. Lake Tahoe continues to run above full pool, with a water level of 6,227.26 feet as of April 4.
(MORE: Spring Flood Outlook)
As the snow melts this spring, any heavy rain events could pose additional flood risks. Flooding concerns may also increase if the weather turns warm for an extended period of time this spring.

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