It sounds like something out of, say, The Dark Crystal: An alignment of the weather, the sun, the moon, and the Earth that causes the ocean to rise up to new heights. But that's exactly what's happening in the Bay Area this week, causing flooding and dangerous conditions for boaters and beachgoers from today through Thanksgiving.

According to the Chron, the extreme high tides (or "king tides," as they are also known) kick off at 8:45 a.m. today, and are expected to reach a height of 6.89 feet. At 9:27 a.m. Wednesday they'll hit their peak at 6.98 feet, and will start to taper off Thursday at 6.92 feet at 10:09 a.m.

This week's tidal phenomenon is happening because "the sun, moon and Earth are aligned...there is a full moon and Earth is directly between the two celestial bodies, creating a doubly strong gravitational field," the Chron reports. This alignment coincides with the cold, rainy weather also expected for this week, and the two might combine to cause "flooding of coastal Marin and low lying areas around the San Francisco and Monterey bays" and "a potentially dangerous tidal situation," the Coast Guard says in a written statement.

We have places around the periphery of the bay that are very close to mean high tide so, even if it only goes a few inches above, these places get some flooding," Jan Null, a meteorologist for Golden Gate Weather Services, tells the Chron, citing spots like "underneath Highway 101 in the Manzanita parking lot in Mill Valley, along the Embarcadero in San Francisco, at various spots along the Peninsula and in the communities of Bolinas, Sausalito and Tiburon."

But what might be bad news for the Embarcadero is good news for birds, as Chron outdoors writer Tom Stienstra says that the unique conditions will also provide miles of feeding ground for migrating waterfowl and shorebirds as the tides drop back in the afternoons.

All of this makes for a potentially hazardous situation at the beach, as folks off work for the holidays come out to see the high waves and dining birds, but the Coast Guard says they're on it.

According to Andrew Cohen, the command duty officer for the U.S. Coast Guard in San Francisco, his agency “encourage[s] all persons on or around the coast to remain especially cautious during this storm system,”

“We stand ready to respond if boaters and beachgoers find themselves in distress,” Cohen says, but "be aware that weather conditions can change quickly."

Related: Winter Is Coming (This Week)