Information on the Monthly Tide Prediction Charts
Minas Basin & Halls Harbour
Interpreting the Charts
 
~ Get month's tide at a glance ~
Minas Basin (Horton Bluff) & Halls Harbour
Also refer to this excellent article on Fundy Tides by Roy Bishop
 
Background
The charts are NOT designed to be used for navigation at sea! Instead, it is offered as a recreational guide giving a general, "wide angled view", of the ebb and flow of tide waters in the general areas implied. Using a chart, one can see at a glance, approximately what the tide is doing for a particular day or throughout the whole month. With a little skill, one can estimate tidal events to within 10 or 15 minutes. This is well within a practical limit involving tide schedules for recreational and more general pursuits.
 

Tide time in the Minas Basin, at Horton Bluff, is approximately one hour later than in the outer Bay of Fundy, at Halls Harbour. The major part of the delay is caused by a constricting headland, the Cape Split-Cape Blomidon Peninsula. The interaction of tide and landform result in a tremendous current and tidal rip in this area.

 
Tide height increases as the incoming tide progresses up the Bay of Fundy from the Gulf of Maine, with the greatest tides occurring at the head of the Bay of Fundy in Minas Basin and Chignecto Bay, for example, a 7 to 8 metre tide at St John, New Brunswick, will become a 14 to 15 metre tide in parts of the Minas Basin. Over all, the highest tides have been recorded at the eastern end of Minas Basin at Burntcoat Head. In the Minas Basin, tide typically ranges from about 10 metres to 14 metres during the month, which, on any day, is as much as 2 metres greater than it was at Halls Harbour.
 
When perigee (the Moon's closest distance from Earth) coincides with a Full or New Moon, the tide will exceed 15 metres (13 m at Halls Harbour ). When the distance between Earth and Moon is greatest (apogee), especially when it coincides with one of the Quarter Moons, tide range is limited to between 8 and 9 metres (7 m & 8 m at Halls Harbour).
 
Horton Bluff (near Avonport, Nova Scotia, 45° 6.4' N, 64° 13.5' W)
The Horton Bluff chart is a reasonably good guide for the tide schedule and height around the Minas Basin, especially along the southwestern shoreline (Hantsport, Avonport, Grand Pre, Wolfville, Port Williams). It is also a reasonable tide guide for shorelines extending from Windsor to Truro (5 to 10 minutes later). At Parrsboro and Blomidon the tide picture is similar, except, times will be about 15 to 20 minutes earlier than at Horton Bluff.
 
Halls Harbour (45°12' N, 64° 38' W, on Fundy Shore, north of Kentville, Nova Scotia) 
Most comments made for Horton Bluff apply to the Halls Harbour chart, except for the part of the Bay it typifies. The predictions for Halls Harbour can be used as a good guide for the upper end of the Bay of Fundy, outside Minas Basin (Harbourville, Baxter's Harbour, Scott's Bay, Cape Split, Spencer's Island, Advocate, also Alma and Fundy National Park on the N. B. side of the Bay).
 
Reading the Charts
Tide Time  (Note: Graphs shown in this section are samples from an earlier month.)
The upper graph (sample below) gives predicted tide times. The large blue and green square dots represent time of High Tide. The smaller black and red dots represent time of Low Tide. The vertical line on which the coloured dots are placed, represents a 24-hour day, the intersecting horizontal line marks off a 1-hour interval of time. The time value is obtained from the number to the left or right.
Tidal Bore Time (Horton Bluff Chart only) 
The "+ sign" represents a predicted time for when the tidal bore comes into view at Tidal View Farm , located on the St. Croix River in Hants County, between Miller Creek and Avondale. The tidal bore arrives at the (now improved) Mantua bridge over the Herbert River, 35 to 45 minutes later. Also, by adding 2 hours to "in view" time at Tidal View Farm, one will be very close to the arrival time of the tidal bore at the Tidal Bore Motel viewing site on the Salmon River near Truro, N.S. The best days for viewing a tidal bore are on the days having the greatest range of tide; these usually follow a New or Full Moon, especially when perigee is near one of these Moon stages.
 
Sunrise/Sunset Time 
Sunrise and sunset times are indicated by an orange line. The sunlit portion of the month is tinted pale yellow. The times of sunrise and sunset indicated are for latitude 45.1 N, longitude 64.25 W (Horton Bluff, N.S., near Avonport). The times are intended as a guide to the general picture of sunrise/sunset relative to tidal events.
 
Height and Range of Tide 
The second part of the graph (sample below) depicts height and range of tide, from high to low in relation to the other tides of that day and throughout the month . It also relates tide height and range to Moon and Sun position as implied by phases NM, FQ, FM, LQ, as well as the Moon's distance: P=perigee and A=apogee.
 
Range of tide is the vertical rise of tide from the water level at Low Tide on a particular day, to the water level at the next High Tide. Tide is tinted a pale shade of blue.
Height of tide refers to the depth of water above datum.
Datum is the point of reference below which low tide seldom falls.
During New and Full Moon (NM, FM), lunar and solar tides are synchronized and result in tides of greater range: spring tides (nothing to do with season).
 
During First and Last Quarter Moon (FQ, LQ), lunar and solar tides are unsynchronized, resulting in tides of lesser range: neap tides.
 
About every 27.5 days the Moon's elliptical orbit places the Moon at its nearest point to Earth, known as perigee. Perigee (P) increases the range of tide significantly, especially when it occurs near a Full or New Moon. Apogee (A), the far point between Earth and Moon, has the opposite effect. The tide chart shows these effects quite readily.
 
When perigee and Full Moon are fully synchronized (happening on the same day) , Fundy tides are very large (in the Minas Basin, such tides can range through 16 metres). During the 206 days following such a situation (a bit more than a half year), perigee gradually falls out of step with Full Moon and aligns itself with New Moon. Perigee and New Moon are now synchronized and the largest tides will then follow New Moon. In contrast, when perigee is with the Full Moon, apogee is usually with New Moon, having the effect of making a New Moon tide more like a neap tide, and vice versa.
 
S, E, & N represent the Moon's position in the sky relative to the equator (declination). This factor causes our part of the earth to pass more directly or less directly under the Moon's tidal influence. When the Moon is at its maximum Northern or Southern declination, one of the day's tides tends to rise a bit higher and drop a bit lower than the other. When the moon declination puts it overhead at the Equator, the two high and two low tides for the day rise and fall about the same amount.
 
You will notice, also, that the maximum tidal response frequently lags a day or two behind the maximum astronomical input conditions.
 
The bottom of the tide chart has an explanation of symbols used along with a few accompanying notes.
 
If you are not on the Minas Basin or would like specific numbers, return to the main TIDES page.
 
Minas Basin scene at rising tide-NA.
 
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