The largest annual tidal range can be expected around the time of the equinox if it coincides with a spring tide.Sustained storm-force winds blowing from one direction combined with low barometric pressure can increase the tidal range, particularly in narrow bays.Larger bodies of water have higher ranges, and the geography can act as a funnel amplifying or dispersing the tide.[5] The world's largest mean tidal range of 11.7 metres (38.4 feet) occurs in the Bay of Fundy, Canada (more specificially, at Burntcoat Head, Nova Scotia).[8] The fifty coastal locations with the largest ranges worldwide are listed by the National Oceanic and Atmospheric Administration of the United States.
The
M
2
tidal constituent
, peak
amplitude
indicated by color. White lines are
cotidal
lines spaced at phase intervals of 30° (a bit over 1 hr).
[
3
]
Amphidromic points
are the dark blue areas where the lines come together. These are amphidromic points, NOT tidal ranges. Tidal ranges can vary from 4 to 10 times what's marked on this map.