Powerful storms drenched the East and West coasts over the weekend, shattering rainfall records in the Washington, D.C., area and creating office tower-sized waves off the California coast.

Tweeting in all-caps Saturday afternoon, the National Weather Service issued a warning to surfers and gawkers in Northern California: “STAY WELL BACK FROM THE OCEAN OR RISK CERTAIN DEATH.”

Waves exceeding 50 feet in some areas could persist into Monday in what the weather service described as the “largest wave event of the season.”

The surf was so dangerous, the World Surf League canceled events in its “big wave tour” at the legendary Mavericks surf spot south of San Francisco, NBC Bay Area reported.

A surfer rides a wave at Mavericks in Half Moon Bay, California, on Dec. 17, 2018. Ezra Shaw / Getty Images

“I think they were more worried about the wind and the height,” Frank Quirarte, who runs the Mavericks rescue team, told the station Sunday. “Even the most experienced guys will tell you that’s something they don’t want to do.”

The surf was the largest Quirarte had seen at Mavericks in a decade, NBC Bay Area reported.

Forecasters expected rainfall totals from one to three inches across the San Francisco Bay Area, according to the station.

Howard County Fire and Rescue save a llama from flooding Sunday in Mink Hollow, Maryland. Howard County Fire and EMS

Outside Washington, crews in Fairfax and Montgomery counties rescued multiple passengers from stranded vehicles, officials said. In Howard County, they rescued a llama from a flooded pasture near the swollen Patuxent River.

The rescues came amid record-breaking rains recorded in Baltimore, Washington and at Dulles Airport, the National Weather Service said.

Daily rainfall totals more than doubled at Dulles, rising from a previous record of roughly one inch in 2005 to nearly 2.5 inches on Saturday, the weather service said.

Rainfall records for the area had been broken only one day before, when the weather service reported that 2018 was the wettest calendar year ever recorded at Washington National Airport. The old record of 61.33 inches had been documented more than a century before, in 1889, the agency said.