Florida's Atlantic coast stayed under coastal flood warnings on Tuesday, October 27, as a round of unusually high tides, known as king tides, lined up with steady northeast winds. The warnings do not share one end time, so the useful date depends on where on the coast a reader is.

In South Florida, the National Weather Service office in Miami kept a coastal flood warning in effect until 8 p.m. EDT Wednesday for coastal Miami-Dade, Broward, and Palm Beach counties. Palm Beach County also had a high surf advisory until the same time, with breaking waves of 8 to 13 feet, and a high rip current risk through Wednesday evening.

The Florida Keys had a separate warning for major saltwater flooding. That warning ran until 5 a.m. EDT Wednesday, with the strongest concern around high tide in the Lower and Middle Keys and little relief outside high tide in the Upper Keys. Readers in the Keys should check the current Key West bulletin before travel, because the Keys warning ends earlier than the warnings farther north.

Why the water is running high

A king tide is an especially high astronomical tide, and this round fell close to the full moon. Persistent northeast winds pushed water farther ashore and slowed its return to the sea. Scott Kelly, a meteorologist with the Weather Service in Melbourne, said the peak high tides were expected on the mornings of October 27 and 28, and described this round as one of the higher tides of the season.

At Trident Pier in Port Canaveral, the high tide on October 26 reached 3.02 feet above mean higher high water, which the Weather Service in Melbourne described as the highest non-tropical water level observed there since 1994. Mean higher high water is a reference level: it is the long term average of the higher of each day's two high tides at a gauge. A reading of 3.02 feet above that level means the gauge stood 3.02 feet above that average higher high tide. It does not mean every nearby road had three feet of water on it.

On the Treasure Coast, Martin County officials reported flooding on Southeast MacArthur Boulevard on Hutchinson Island and on Indian River Drive, along with flooding in Old Palm City and South Sewall's Point. County officials also reported beach erosion. Those are reported locations, not a complete list of closed roads, and conditions at any one road can change with the next high tide.

What the warnings mean on the ground

Farther north, the Melbourne office warning ran until 2 a.m. EDT Friday for coastal Volusia, Indian River, St. Lucie, and Martin counties and for mainland and barrier island Brevard County. That warning covered surf of 7 to 11 feet and a high rip current risk through late Thursday night. Forecasters said coastal roads could close, low lying property could be inundated, and significant shoreline erosion could occur.

The Jacksonville office warning for northeast Florida beaches also ran until 2 a.m. EDT Friday, with surf of 7 to 10 feet and a high rip current risk through late Thursday night. A separate Jacksonville warning for the St. Johns River Basin covered moderate flooding during high tide, also until 2 a.m. EDT Friday, for inland Flagler, eastern Clay, eastern Putnam, the Trout River, south central Duval, and western St. Johns. Beach surf and river basin flooding are different hazards, even though they share the same end time in this bulletin.

For safety, the Weather Service advice is direct: protect flood prone property, do not drive around barricades, and do not drive through water of unknown depth. Stay out of the surf where a high surf advisory or high rip current risk is in effect. If caught in a rip current, relax and float, do not swim against the current, swim in a direction following the shoreline if able, and face the shore and call or wave for help if unable to escape.

When conditions should ease

Conditions should begin improving later in the week as the coast moves further past the full moon and the king tides. Until a warning expires, check the current Weather Service bulletin for your county before driving a coastal road or heading to the beach, because high tide times and warning end times differ by location.

For a local bulletin, use these official pages, which change as warnings are updated:
- Miami office coastal flood warning
- Key West office coastal flood warning
- Melbourne office coastal flood warning
- Jacksonville office coastal flood warning
- National coastal flood warning summary