Waves up to 20 feet high expected along Bay Area beaches 

The beaches in the Bay Area are expecting waves up to 20 feet tall, creating dangerous conditions for beach-goers, the National Weather Service announced on Monday. 

"There is a northwest swell that is coming in ahead of [Tuesday's] cold front," said Dalton Behringer, a forecaster with the weather service.

The National Weather Service warned beach-goers to "never turn your back to the ocean" because of an increased risk for sneaker waves. 

Sneaker waves are larger and go further up the beach than normal waves, catching many people on the beach by surprise and dragging them into the ocean. 

"There can be an interval up to 30 minutes between large waves," Behringer said. "People may look out at the water and think it's not that bad, and then the wave comes out of nowhere and sneaks up on you."

The beach hazard alert was issued for beaches from Sonoma County to Monterey County. Behringer said the most dangerous conditions will likely be found at northwest-facing beaches such as Pacifica State Beach. 

The wave warning comes ahead of a cold front that is expected to hit the area, bringing light rains and breezy winds to the region on Tuesday.