Boston’s Long Wharf is flooding.
This flooding is part of a “king tide” – a tide higher than all others. When the sun, moon, and Earth are in alignment, and close to each other, the tides will have especially high amplitudes – that is, the highest high tides and the lowest low tides. If you want a general introduction to how tides work, check out this Crash Course Astronomy video.
So, with this week’s supermoon, the tides are especially strong – some of the strongest of the year. During high tide, salt water is sneaking through storm drains and spilling over seawalls all along our coasts.
This kind of flooding is often called “nuisance flooding” or “clear-day flooding” because it isn’t associated with storm surges or winds. But let’s be clear: this “nuisance flooding” is exactly how sea level rise works.
What’s more, these floods will become more common as sea level rises.