King tides are back this weekend. If you’re wondering what they are, here’s some background

King tide is back, South Florida, so don’t put away your galoshes yet.

Annoying street flooding will test your patience for the next few days as water crashes over seawalls and bubbles up through drains and sewers. And there’s not much we can do aside from adjusting our lifestyles.

Here are some basic facts about the annual phenomenon.

What are king tides?

Twice a month during the full and new moons, tides rise higher as the sun, moon and Earth align. Those are called spring tides. But twice a year — in the spring and fall — spring tides become king tides when the Earth’s northern hemisphere is closest to the sun. The fall king tides are more extreme. According to FAU professor Colin Polsky, “we don’t really pay attention to the spring event because those tides aren’t high enough to cause flooding compared to the fall, when the tides are high enough to cause flooding.” The scientific name for king tides is perigean spring tide.

Are they caused by climate change?

King tides are a worldwide, naturally occurring phenomenon made worse by climate change and sea level rise — though not caused by either. Scientists do think today’s king tide levels offer a look ahead in time at what normal tides will look like in a decade or two.

When is spring tide?

King tide dates are not scientifically exact, so you may see variations depending on the source. Locally, the City of Miami website lists Nov. 14-17, while the City of Fort Lauderdale website lists Nov. 13-18. Also, some organizations on the west coast list dates in December and even January. We don’t pay attention to those on this side of the country. Although king tides are felt equally around the world, AccuWeather meteorologist Derek Witt said timing varies. “There will be some slight difference because the tides will vary based on the exact position of the alignments of the moon and the earth and the sun given the time that the king tides are going on,” Witt said. Other factors including water temperature and ocean currents affect the timing of king tides in a particular location, said University of Florida professor Ashley Smyth.

What can we expect in South Florida?

In South Florida, street flooding is the most obvious symptom of king tides, but it doesn’t happen everywhere. Polsky said. “How wet the streets get from these higher tides in one place depends on the elevation of the land in that place, and elevations may differ from place to place.” Numerous parts of Las Olas Boulevard in Fort Lauderdale, the Marina Historic District in Delray Beach and Brickell Avenue near downtown Miami will flood. Some streets become so flooded that residents put up “No Wake” signs so cars won’t create waves that push water into their houses. Debris will clog drains and make flooding worse. South Florida will be a mess. Guaranteed.

Are low tides especially low during king tides?

Yes, if a big tide comes in, it must also go out. “A consequence of king tides bringing high water levels is that low tide is also very low, and you can see more of the sediments or the beach might seem bigger,” Smyth said. At least one spot in California reveals cool things as the ocean recedes. “The extreme low tides, which have proven particularly popular, expose tide pools rarely seen and allow miles of beach walking and extended exploration,” the Santa Cruz, Calif., website says. Here in South Florida, even when the water is at its lowest, there isn’t much to see except sand and sediment.

Do king tides happen elsewhere on the east coast?

Fort Lauderdale and Miami are extremely vulnerable to king tide flooding. But there are also notorious king tides in Annapolis, Md., Boston, around the northern Chesapeake Bay as well as areas in Virginia, North Carolina and South Carolina. In the northeast and southeast, king tides this year will occur around Nov. 14-18 and in the mid-Atlantic will start a day earlier.

What about on the Gulf Coast of Florida?

Surprisingly, there aren’t significant impacts from king tide on the U.S. Gulf Coast. “In many locations of the Gulf Coast,” NOAA said, “the tidal range is relatively small compared to other regions of the U.S, so they will not be as significantly impacted by a perigean spring tide.” Witt said the topography of the Gulf makes the tide less exaggerated.

King tides on the Pacific coast

Similar to the east coast, king tides will impact the west coast Nov. 13-18 this year. San Francisco is especially impacted with flooding, but NOAA doesn’t list other locations specifically. “In November, some locations along the West Coast are predicted to exceed the high tide flooding threshold based on tides alone,” NOAA said. The dates are the same in Alaska but in Hawaii, king tides are over for the year, hitting in early July and again in mid-August.

Do king tides happen on the Great Lakes?

The Great Lakes have no tides, and therefore no king tides. The gravitational pull isn’t significant on lakes. They rise and fall a few centimeters as opposed to oceans, which could typically rise and fall a foot or more during regular daily tides.

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