King Tides (also known as perigean spring tides) are extreme high tide events that occur when the sun and moon’s gravitation forces reinforce one another at times of the year when the moon is closest to the earth. They happen twice a year, but they are typically more dramatic during the winter.
While tides are not affected by climate change, the climate and weather do influence coastal sea levels through storm surges, the ENSO and PDO cycles and other factors. Storms that occur during high tides can cause coastal flooding and erosion, a risk that will increase with sea level rise.
Global sea levels have risen approximately 20 cm since the industrial revolution. Even with immediate and dramatic reductions in greenhouse gas emissions, sea level rise is expected to accelerate and to potentially continue for centuries. Climate change will affect sea levels on the British Columbia coast.
Snap the shore. See the future.
King Tides offer us a chance to visualize what normal sea levels may look like in the future. The King Tide Photo Initiative captures images of coastlines around the world where infrastructure and ecosystems are vulnerable to flooding due to sea level rise. BC invites citizen scientists along the BC coast to share photographs of King Tides in their region using social media.
On the ground
Open the King Tides Chart for the season to see when the best time for you to snap the shore is!
Visit the Facebook Events listing to see what organizers are doing in your community.
King Tides in Other Jurisdictions
BC 's King Tide Photo Initiative is modelled after a similar project conducted by Australia’s Department of Environment, Climate Change and Water: A Snapshot of Future Sea Levels: Photographing the King Tide Event (PDF, 2.6MB). The State of Washington’s Department of Ecology has also conducted similar documentation: Extreme High Tide Events.
Find out more about the numerous King Tides Photo Initiatives happening globally on Kingtides.net.