What Is a King Tide? Red Tide Algae, Flooding Among Risks From Highest Tide of 2018

The King Tides will come rolling in this weekend from Florida to the mid-Atlantic states, bringing a risk for toxic red tide exposure in south Florida and flooding risk to spots along the East Coast. They are expected to be the highest tides of 2018. At greatest risk for tidal flooding from October 7-10 are coastal areas in Southeastern states, including Georgia, Florida, and South Carolina. The peak high tide day is October 9.

Mid-Atlantic states including New Jersey, Delaware, Pennsylvania, Maryland, District of Columbia, Virginia will also experience high tides, with flooding potential at Kings Point, New York and Providence, Rhode Island according to NOAA.

In Florida, the higher tide forecast has led officials in the Miami area to warn residents to avoid the king tide floodwaters expected over the weekend because the higher waters may bring in toxic red tide algae, detected earlier this week near the Miami area.

Red tide can cause allergic reaction in humans including eye and nose irritation. Scientists said this year's annual highest tides could push poisoned water further onshore, spreading red tide's impact, the Miami Herald reported.

"I'm hoping its going to be dead by then, but you can't count on it," said Stephen Leatherman, a coastal environmental scientist at Florida International University. "I'm hoping for the best."

The city of Miami has warned residents to avoid contact with floodwaters during the high tides, known as King Tides, expected October 7 through 10 with a peak on October 9, according to NOAA. Also, NOAA says these southeastern locations have the highest chance of flooding from the high tides: Myrtle Beach, South Carolina; Charleston, South Carolina; Fort Pulaski, Georgia, and Fernandina Beach, Florida.

What is a King Tide?

A King Tide is a colloquial term commonly used to describe unusually high tides that occur during a new or full moon and when the moon is at perigee once every 28 dates. The moon reaches perigee on Friday, October 5 and reaches the new moon phase on October 8, resulting in a perigean spring tide.

The perigean spring tide occurs three or four times each year when the new moon occurs close in time to the moon perigee, when the moon is closest to earth in the month. The perigean spring tide impact is small, typically raising water a couple of inches above normal tides but at peak they can be higher. This perigean high tide is expected to be the most significant of the year.

Beaches in the Miami-Dade area were closed on Thursday for red tide algae but they are expected to reopen today. Red tide is typically found in the Gulf of Mexico, so the occurrence near Miami caused some concern.

"While red tide is rare on Florida's Atlantic Coast, officials confirmed that it had reached waters off of Palm Beach County Monday evening," weather.com reported. "Testing was expanded along the East Coast, including four beaches in Miami-Dade County and sections of Broward County, as well as waters two miles offshore."

What Is a King Tide? Red Tide Algae, Flooding Among Risks From Highest Tide of 2018 | U.S.