The rise and fall of the tides in the Anchorage Alaska area are typically 30 - 40 feet. Here in North Carolina the tides rise and fall maybe 2 feet. What is causing this difference? Is it latitude? Does the same phenomenon take place in the extreme southern latitudes?
NC
Posts: 1641 | Location: North Carolina, USA | Registered: 06-03-02
To be honest, I don't know, but after some researching, the answer doesn't seem that simple since there are so many things effecting the level of the tide, not least of which is the shape of the coastline itself. I did see some questions of high tides observed in Alaska on other sites, but no explanation as to why it might be, except my interpretation that it could be connected to the shape of coastline, with narrow bays or some such.
Here is a site with more information on what influences tides.
The earth is constantly moving, and everything on the earth is affected by the gravity, the movement, and even to a certain extent, the gravity of nearby bodies. So naturally, the water that makes up 70% of the earth's surface is constantly sloshing around.
If you take a bowl of water and tilt it back and forth, the level of the water at the left and right edges will rise and fall the most, while the levels at the front and back may not change much at all, since they're along the axis of the shifts. The difference between Alaska's tide shift and NC's tide may be for a similar reason.
Posts: 3632 | Location: Washington, US | Registered: 06-03-02
I believe that not only the shape of the coastline, but also the geological formation (ledge and mountains versus permeable soils) of the nearby shores determines the tidal range. The water tends to bunch up against the rocky coast and cause higher tides. There is an 11 foot tidal range in my area, with high and low tides about 6-1/4 hours apart. I would love to see the areas with the 40 foot ranges, since between low and high tides the water would rise an incredible 6 feet per hour, or about a foot every ten minutes!
Posts: 625 | Location: Boston | Registered: 06-13-02