UPDATED: Earthquake in Russia prompts tsunami advisory on the West Coast, including Monterey Bay.

An 8.7-magnitude earthquake hit about 80 miles southeast of Petropavlovsk Kamchatka in Russia at 4:25pm on Tuesday, July 29. The quake prompted the National Weather Service to issue tsunami warnings and advisories along the West Coast of the U.S.

The earliest a tsunami is forecasted to start is in British Columbia at 10:05pm Tuesday night, followed by Crescent City at 11:50pm. The forecast anticipates activity could start in Monterey at 12:15am Wednesday morning, July 30. It's expected to begin in La Jolla and Oceanside at 1:15am. 

"If you are located in this coastal area, move off the beach and out of harbors and marinas," the Weather Service advises. "Do not go to the coast to watch the tsunami."

At about 9:40pm, the Monterey County Sheriff's Office issued an evacuation warning for Moss Landing Harbor; the Monterey Police Department issued an evacuation warning for the Monterey Harbor. (A warning means people should prepare for a possible evacuation order.) 

A tsunami may not look so dramatic at first, the Weather Service cautions: "Tsunamis often arrive as a series of waves or surges…the first tsunami wave or surge may not be the highest in the series."

The impact and localized flooding can last for hours after the initial arrival time. The forecast for Monterey anticipates a height of up to 1 foot of water.

The advisories for Monterey and the surrounding areas mean strong currents and dangerous waves are expected. Tsunami warnings, more serious than advisories, have been issued in Hawaii and Alaska, meaning dangerous flooding is possible and people are encouraged to move to higher ground.

The Weather Service also notes that many areas outside of its jurisdiction—along the West Coast of Central and South America, and Pacific Islands—are under threat.