California officials ramp up preparations as powerful storm threatening heavy rainfall and flooding closes in on millions | CNN

CNN
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Millions across central and Northern California are bracing for an alarming storm beginning Thursday, with heavy rain threatening to cause widespread flooding in areas already mired in the perilous aftermath of dayslong snowfall.

More than 17 million people are under flood watches in California and slices of Nevada, with much of the Golden State under an especially significant risk of excessive rainfall that can flood neighborhoods – flooding that could swamp some of the same areas already devastated by severe flooding earlier this year.

“An atmospheric river will bring anomalous moisture to California Thursday and Friday. The combination of heavy precipitation and rapid snow melt below 5,000 feet will result in flooding,” the Weather Prediction Center said, adding that “numerous” floods are likely for millions.

The most vulnerable areas for flooding from rain and snowmelt are creeks and streams in the foothills of the Sierra Nevada, the prediction center said. “This will lead to difficult travel, and combined with an already deep snowpack, may lead to increasing impacts from the depth and weight of the snow,” the prediction center added.

Northern California can expect to see rain and snow beginning late morning Thursday, with rainfall set to steadily intensify over the central and the northern parts of the state through early Friday morning.

The bleak forecast moved officials across central and Northern California to urge residents to prepare, with residents in one area advised to stock up on essentials for two weeks, while others were asked to use sandbags to protect their properties and clear their waterways to lessen any flooding impacts. Plus, 34 of California’s 58 counties are under a state of emergency issued by the governor’s office due to the previous storms and this week’s severe weather.

Here’s what else the storm could bring:

• Heavy rainfall: Most urban areas could see between 1.5 and 3 inches of total rainfall, according to the National Weather Service in the San Francisco Bay Area. The threat heightens for coastal ranges and inland hills, where between 3 and 6 inches of rain are expected, the weather service added. The Santa Cruz Mountains may see up to 8 inches of rain while local areas with higher terrain may collect up to 10 inches of rain over a prolonged period of time.

• Ferocious winds: More than 15 million people across northern and central California, northern Nevada and southwestern Idaho are under high wind alerts. Wind gusts could reach up to 55 mph across lower elevations and up to 70 mph across peaks and mountains. Strong winds could knock down power lines and trees, which would occur against the backdrop of thousands of existing power outages from previous storms whose heavy snow wreaked havoc particularly in areas of higher elevations.

• More heavy snow: Parts of the Sierra Nevada mountain range above 8,000 feet could see snow pile up to 8 feet. Also, parts of higher elevations across southern Oregon and the Rocky Mountains in Idaho, Montana and Wyoming could see up to 2 feet of snowfall between Thursday and Friday.

Many of the areas preparing for Thursday’s storm have not had a chance to recover from the multiple consecutive rounds of heavy snow that buried some neighborhoods and made roads inaccessible for days as residents ran low on essential supplies. In hard-hit San Bernardino County, one of the recent storms claimed the life of one resident in a car crash, the county sheriff’s department told CNN on Wednesday.

The imminent powerful storm has put some local officials in preparation mode days ahead of its expected landfall as a strong atmospheric river, which consists of long, narrow bands of moisture in the atmosphere that transport warm air and water vapor from the tropics.

As the storm hits central California, some urban flooding, ponding and flooding from the smaller creeks and streams is likely. Eventually more roads are expected to flood as the main rivers rise, according to meteorologist Katrina Hand at the Sacramento office of the National Weather Service.

Officials in San Francisco urged small businesses to clear storm drains, stock up on inventory, use sandbags and ensure equipment is properly stored, according to a news release. Officials also suggested that employers should consider adjusting their workers’ schedule for their safety.

Meanwhile, crews in Merced worked to clear storm drains and fortify creek banks ahead of the storm, city officials said in a release, noting that flooding from the deadly rounds of atmospheric rivers that battered much of the state in January has made the city’s water ways unsafe.

“The city urges all residents to avoid these waterways and walking paths,” officials said in the statement. “Because of ground saturation and erosion from prior storms, expect to see more debris in creek flows.

Farther west on the coast, five Monterey County parks will close Thursday and Friday due to the storm’s threat, officials said in a Wednesday tweet.

Plus, officials advised residents in the Big Sur area in Monterey County to ensure they have enough food and other essentials for at least two weeks. The Big Sur area, a roughly 90-mile stretch of California’s central coast, is one of the area’s renowned tourist attractions with rugged cliffs, mountains and hidden beaches along the Pacific Coast Highway.

In Kern County, home to Bakersfield, fire officials urged residents to create emergency kits and to be aware of escape routes and safe areas to seek shelter if needed. Officials also encouraged the use of sandbags to protect properties.

And in San Luis Obispo, city officials said residents should be informed on flood insurance policies and be prepared to both protect their homes and possible evacuations.

In Sacramento, city officials said they intend to open overnight warming centers beginning Friday in preparation for the expected heavy rainfall and low temperatures.