The Department of Environment is appealing to Cayman Islands residents to help document the incidences of ‘king tides’ – much higher-than-normal tidal surges – that are expected early this year.
King tides, also knows as perigean tides, are caused by several factors, including the proximity and alignment of the sun and moon to the Earth. The National Oceanic and Atmospheric Administration describes king tides as long-period waves that roll around the planet as the ocean is “pulled” back and forth by the gravitational force of the moon and the sun as these bodies interact with the Earth in their monthly and yearly orbits.
Higher-than-normal tides typically occur during a new or full moon and when the moon is closest to the Earth, or at its perigee.
According to the DoE, king tides are expected to occur in Grand Cayman and the Sister Islands in mid-January and again in early- to mid-February, coinciding with the full moons for those months.
A press release from the DoE stated, “Scientists at the National Oceanic and Atmospheric Administration are able to predict these ‘King Tides’ each year and they are not normally considered cause for alarm. However, given our low-lying topography and rising sea levels associated with global climate change, the Department of Environment is keen to begin to better understand potential impacts resulting from these events. Depending on the location of the sun and moon relative to the Earth at the time, tides may rise just a few inches to a couple of feet above normal.”
The DoE is requesting residents document higher-than-normal tides by taking photographs and sending the pictures to the department.
“In recent years we are aware of increasing instances of seawater from King Tides washing into some low-lying local streets or groundwater backing up in storm drains,” said Wendy Williams, manager of DoE’s environmental management unit, in the press release.
“Unfortunately, we don’t currently have any annual, reliable observations of these occurrences. DoE staff members will document the high tide incidents they are aware of, but more eyes watching are always helpful.”
In September 2014, king tides knocked over casuarina trees along Frank Sound and eroded local beaches, when tides rose up to 12 inches above sea level, according to data collected by a monitoring sensor at George Town Harbour. Residents in low-lying and coastal areas, including Snug Harbour, North Sound and Red Bay, reported flooding due to the high tide at the time.
Referring to the upcoming king tides, Environment Minister Dwayne Seymour said having better annual records of high tide events “can help us to understand what a future sea level rise might look like, and thus aid in making preparations for such an event”.
He added, “I would encourage Cayman residents to participate and help us to document these events so we can learn from them.”