Throughout the weekend, a cold front supercharged by tropical precipitation brought snow and heavy rain to some urban rooftops in Southern California, with more in the forecast.
Extreme late-winter weather also affected the Midwestern and Plains states on Sunday.
Federal forecasters reported that the leading edge of the weekend storm in California was moving east and creating havoc as it continued to suck warm energy and conflict with cold air.
On Sunday, a squall line was moving into Oklahoma with multiple tornadoes and severe thunderstorm warnings. The National Weather Service office in Norman, Oklahoma, described the front as a "remarkable, perhaps historic storm system."
Forecasters blamed a derecho, or line of sustained, high-speed winds of up to 110 mph, which exceeds the hurricane-force threshold.
According to federal forecasts, the extreme weather also affected the Texas Panhandle and southeastern Kansas, where severe thunderstorms and strong wind advisories were in place.
According to the forecasting agency, most of the country, including the Pacific Northwest, Upper Midwest, and Northeast, will experience snowfall overnight.
According to grid tracker PowerOutage.us, Michigan households and businesses without power decreased to roughly 300,000 on Sunday afternoon from nearly 800,000 on Thursday.
According to the National Weather Service, many inhabitants of high desert settlements and Southern California valleys, such as Antelope Valley and the San Gabriel Valley, awoke to snow on Saturday.
Saturday snowfall was also captured on camera in Rancho Cucamonga and Fontana, San Bernardino County.
Unprecedented amounts of snow were recorded in the mountains spanning from the Sierra Nevada to the Peninsular Ranges in southern California, which extend into Mexico.
Central Sierra Snow Lab at the University of California, Berkeley, tweeted that Donner Peak had received nearly 1.5 meters of snow in the past four days. According to the National Weather Service, Mount Baldy near downtown Los Angeles measured more than 3 feet, and Mount Laguna in San Diego County reported more than 2 feet.
At Mountain High Resort in Wrightwood, located around 75 miles east of Los Angeles, more than 6 feet of snow fell in less than a week, with 5 feet falling in a single day. It snowed so heavily that the resort had to close on Saturday to "dig out and clean up with the available staff."
The snow, rain, and wind caused road closures and flooding in rivers and washes in California as the storm travelled overnight from Oregon to the south and east.
Grapevine, the primary route to San Francisco, was closed due to heavy snowfall and ice on Interstate 5. Sunday afternoon, according to the California Highway Patrol, it reopened.
Saturday, the city of Big Bear Lake issued a warning that all roads leading to the village encircled by the San Bernardino National Forest were blocked due to snow, with no reopening estimate provided. Yosemite National Park has announced that it will be closed until Wednesday due to severe winter weather.
Sunday afternoon, more than 76,000 California homes and businesses were without power, according to PowerOutage.us.
Over four days, Los Angeles County received several inches of precipitation. According to the weather service, Topanga Canyon near Malibu had 6.7 inches of rainfall, Pasadena recorded 7.84 inches, and downtown Los Angeles received 4.3 inches.
Three recreational vehicle trailers were parked at the Valencia Travel Village RV Park in Castaic, in northern Los Angeles. Overnight, residents of Santa Clara County were washed away by the storm-swollen Santa Clara River, requiring a helicopter search-and-rescue team from the nearby Ventura County Fire Department to respond.
According to the fire service, a trailer was discovered, but no victims or injuries were recorded.
Those without shelter were most at risk from the severe rain. Saturday, a helicopter rescue crew in Los Angeles pulled two homeless individuals stranded on islands of dry ground in the Hanson Flood Control Basin to safety, according to a series of statements from the Los Angeles Fire Department.
The males were unharmed and released at the spot, according to the police department.
According to county lifeguards, Los Angeles County officials closed 24 miles of beach from Nicholas Canyon in Malibu to White Point Beach in San Pedro for over two hours Saturday afternoon after lightning was spotted on the shoreline.
On Interstate-17 in Arizona, where winter storm warnings were also posted for the north, a collision involving around 15 automobiles occurred. An unknown number of individuals sustained non-life-threatening injuries and are receiving care.
According to PowerOutage.us, as of early Sunday morning, over 311,000 utility customers in Michigan were without power due to the ice storm.
The president of DTE Energy, Trevor Lauer, projected that 95% of the utility's customers would have power restored by Sunday when milder weather was expected to settle in.
The utility reported having over 4,000 employees tasked with restoring power and visiting vulnerable residents door-to-door.
The rain-producing front that pummeled California was expected to move east across the country early in the week, bringing rain to the desert southwest, moving into the Midwest and Great Lakes, and eventually affecting the East Coast with fresh rain and possibly snow, according to federal forecasters.
More storms from the Gulf of Alaska were predicted for California and the West. Still, according to forecasters, it was unlikely that any would resemble the peculiar mixture of tropical downpours and snow-capable cold that hit the coast overnight.
Adam Rosen, a meteorologist with the National Weather Service in San Diego, stated, "In the future, these can occur." Yet, they do not occur very often. This was an unusual occurrence here."
