SAN FRANCISCO (KRON) – The National Weather Service has put the San Francisco Bay under a dense fog advisory.

The advisory lasts until 10 a.m. today, and also covers large swaths of the North Bay valleys.

Visibility in some of the areas affected is a quarter-mile or less. People are being advised to “listen for sounds of other boats that may be near you or fog horns and bells from nearby buoys.”

“If you are unable to get your bearings, stay put until the fog lifts but make sure you are in a safe location,” NWS went on to state.