Giant, 30- to 40-foot waves battered parts of the West Coast from Washington State south to Los Angeles, prompting warnings and even an unheard of tweet from the National Weather Service (NWS).
“STAY WELL BACK FROM THE OCEAN OR RISK CERTAIN DEATH,” the NWS San Francisco office posted on Saturday on Twitter, hoping to warn surfers about the perilous dangers of these giant waves.
HIGH SURF WARNING continues in effect along the coast from Sonoma County through Monterey County 9 AM Sun to 9 PM Mon.
— NWS Bay Area (@NWSBayArea) December 15, 2018
STAY WELL BACK FROM THE OCEAN OR RISK CERTAIN DEATH. pic.twitter.com/VNroxlXdJs
The NWS issued high-surf alerts along the coast beginning on Sunday and running through Tuesday, and warning people to be careful on beaches and along jetties.
Another social media post from the NWS, this one from the Portland office, included a photo of the Tillamook Rock Lighthouse with waves crashing over the top of it. The top of the structure is 134 feet above sea level.
An off duty NWS employee captured a large wave topping the Tillamook Rock lighthouse this PM. Large seas will continue well into Monday so please stay off jetties & use caution if you plan on visiting beaches along the Oregon and Washington coastline. #pdxtst #orwx #wawx pic.twitter.com/NWoVCxVcDs
— NWS Portland (@NWSPortland) December 17, 2018
The director of the University of Georgia's Atmospheric Sciences program, Marshall Shepherd, told Live Science that the huge waves were caused by a low-pressure system centered in the Gulf of Alaska, and that while the waves can grow to dozens of feet high, they fortunately don't travel inland like tsunami waves.
Very large extratropical cyclone in the northeastern Pacific, driving rain and mountain snow into Washington/Oregon. Notice the terminator (day/night line) fails to reach far north Alaska as we near the December solstice. Still prelim non-operational #GOES17 imagery past 24 hours pic.twitter.com/dJOCQIcOc9
— William Churchill (@kudrios) December 15, 2018
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