With waves as high as 30ft (9.1m) in some areas of California, the US National Weather Service issued a high surf advisory for the US West Coast through Sunday and cautioned inexperienced surfers and swimmers to stay out of the water.

The weather is blamed for multiple injuries and at least one death after a man was found under debris on the coast. The public was told to be vigilant and to “never turn your back on the ocean”.

Meanwhile, storms across parts of Texas prompted tornado sightings and flight delays on Thursday.

On the West Coast, the NWS warned of possibly “life threatening conditions” for swimmers as storms continued to rock the California coast.”Stay off jetties, piers, and other waterside infrastructure,” the National Weather Service warned in a release on Thursday.California has faced days of dangerous surf conditions.A wharf in Santa Cruz, California, collapsed after it was struck by strong waves earlier this week.In a separate incident, the Marina Police Department responded to reports that an adult man had been swept out to sea on Monday. Rescue officials were forced to call off an air and sea search due to dangerous conditions.Farther up the Pacific Coast, the US states of Washington and Oregon are also under heavy surf advisories until Friday afternoon.Down in Texas, the winter winds brought reports of tornadoes.Jimmy George, the emergency management coordinator for El Campo, Texas, told the BBC that a tornado touched down near his small town of 12,000 people that sits about an hour outside of Houston.Mr George saw the tornado at a distance while on a highway, he said, and locals had reported additional sightings of the same weather event.There were no injuries reported but three barns in the area were damaged, said Russell McDougall, an emergency official in Wharton County, Texas.Local media reported a second tornado in the area, but the BBC was not able to independently verify this.The National Weather Service had warned residents in the Houston area and parts of southeast Texas of the potential for thunderstorms and tornadoes. An NWS spokesperson could not immediately verify the El Campo tornado, as such reports can take several days to officially confirm.More than 100 flights were delayed at Dallas-Fort Worth Airport due to weather, the AP reported.The storm system was expected to pass by Thursday night.The US East Coast, meanwhile, continued to enjoy a snow-dusted Christmas.New York City experienced its first so-called “white Christmas” – when more than an inch of powder is recorded on the ground – since 2009.While snow caused minor travel woes for some on the roadways, it was not the main trouble for Morris County, New Jersey – a suburban area outside near Manhattan.Drivers there faced a large sinkhole that opened up next to the I-80 highway in Morris County, which prompted traffic delays.

The twister flipped over several cars and brought down power lines in Scotts Valley, located around 55 miles (89km) south of San Francisco, police said.

The National Weather Service (NWS) said the tornado was categorised as an EF1, one of the weakest classifications, and that it lasted around five minutes.

Earlier on Saturday, residents of San Francisco had been issued a tornado warning for the first time ever as thunderstorms swept through the region.

In Scotts Valley, the tornado touched down at 13:39 local time (21:39 GMT) on Saturday, police said.

The local fire service said at least four people had been injured and at least two of them had been taken to hospital, CBS News reported.

Police closed a road overnight to allow for repair work to be done and debris cleared.

Wind speeds were estimated to have peaked at around 90mph (145km/h), the NWS said.

The weather agency also said the twister had been around 30 yards (27m) wide and travelled for a quarter of a mile (400m) before subsiding.

Earlier on Saturday, a tornado warning was issued to residents of San Francisco just before 06:00 local time (14:00 GMT).

The warning was for parts of downtown San Francisco and northern San Mateo County.

More than one million residents were woken in San Francisco and its suburbs to alerts on their mobile phones, warning them to “take shelter now”.

Winds of up to 60mph (96km/h) ripped through the area, the NWS said.

But a few minutes later, NWS Bay Area said the warning was over and the storm had moved out of the city’s downtown.

The city last saw a tornado in 2005, though that struck without any clear radar signature, so no warning was issued in that case, NWS meteorologist Roger Glass told AP news agency.

Nearby San Mateo County was last issued a tornado warning in 2011.The warning came after a powerful storm passed through overnight – trees were toppled and there were major power cuts.

As of Sunday, more than 50,000 customers were still without power along the northern and central California coast, according to the PowerOutage website.

NWS Bay Area warned that residents should steer clear of the seaside over the weekend, with a coastal flood advisory in place until Monday.

San Francisco’s tornado alert came just a week after the city saw its first ever tsunami warning.

The brief advisory was issued for northern California and southern Oregon following a magnitude 7.0 earthquake that hit off the northern coast of the state.

It was later rescinded, and no injuries were reported.