are depths on charts at low tide?
151258
Depths are usually described with respect to low water reference planes (yielding lower charted depths, which are safer), and heights are shown with respect to high water reference planes (again, yielding lower vertical clearances on the chart, which are safer).
530383
Yes. Many streams in the West and South have deposits of quicksand as well as many beaches everywhere. ... The deposits may not be very deep, (quicksand is the result of water flowing through sands, and the amount or depth may be very little).
529251
How exactly is sea level measured? THE STANDARD method of measuring is by means of instruments called tide gauges. Gauges exist in many ports and harbours around the world, and record the height of the rising and falling tide relative to a reference level, called a "benchmark", on the land nearby.
1074036
The difference in height between the high tide and the low tide is called the tidal range. A horizontal movement of water often accompanies the rising and falling of the tide. This is called the tidal current. ... The strongest flood and ebb currents usually occur before or near the time of the high and low tides.
101786
Studies indicate that the Great Lakes spring tide, the largest tides caused by the combined forces of the sun and moon, is less than five centimeters in height. ... Consequently, the Great Lakes are considered to be non-tidal. Water levels in the Great Lakes have long-term, annual, and short-term variations.
189227
The highest tides occur when the Moon is new or full. High tides sometimes occur either before or after the Moon is straight overhead. Sometimes there are really low tides called neap tides. Some places have only one high tide and one low tide in a cycle (24 hours and 50 minutes).
635394
Tidal range is the height difference between high tide and low tide. Tides are the rise and fall of sea levels caused by gravitational forces exerted by the Moon and Sun and the rotation of Earth. Tidal range is not constant but changes depending on the locations of the Moon and Sun.
1048223
Spring Tides: The Greatest Tidal Range When the moon is in its full and new phases the earth, sun and moon are all aligned, which means the sun's and moon's gravitational forces coincide. A more pronounced tidal range – stronger high and low tides – results from this alignment.
1061817
More Tidal Facts: The highest tides occur when the Moon is new or full. High tides sometimes occur either before or after the Moon is straight overhead. Sometimes there are really low tides called neap tides.
885696
Spring tides have higher high tides and lower low tides whereas neap tides have lower high tides and higher low tides. Hence, the range (difference in water level between high and low tide) is much larger in a spring tide than in a low tide. ... Spring tide and neap tide levels are about 20% higher or lower than average.
73770
Figure 14.11: High tide is created by the gravitational pull of the moon which pulls water toward it. Water on the opposite side of the Earth is pulled least by the moon so the water bulges away from the moon. High tide occurs where the water is bulging. Low tide occurs where it is not.
529457
A chart datum is generally derived from some phase of the tide. Common chart datums are lowest astronomical tide and mean lower low water. In non-tidal areas, e.g. the Baltic Sea, mean sea level (MSL) is used. A chart datum is a vertical datum and must not be confused with the horizontal datum for the chart.
1463182
Because the Earth rotates through two tidal “bulges” every lunar day, coastal areas experience two high and two low tides every 24 hours and 50 minutes. High tides occur 12 hours and 25 minutes apart. ... This occurs because the moon revolves around the Earth in the same direction that the Earth is rotating on its axis.
266212
When the highest part, or crest of the wave reaches a particular location, high tide occurs; low tide corresponds to the lowest part of the wave, or its trough. The difference in height between the high tide and the low tide is called the tidal range.
1174976
In both cases, the gravitational pull of the sun is "added" to the gravitational pull of the moon on Earth, causing the oceans to bulge a bit more than usual. This means that high tides are a little higher and low tides are a little lower than average.
212144
Higher than normal high tides and lower than normal low tides will occur. Tides will increase in the weeks leading up to and after the June 21 summer solstice, due to the position of the sun relative to the equator. Mean sea level is typically higher due to changing weather patterns and increasing water temperatures.
309117
They show how deep the water is at that point. Large block letters at the top and bottom of the chart indicate the unit of measurement used for soundings. So NOAA SOUNDINGS can be in FATHOMS (1 Fathom = 6 feet), FEET, or METERS (1 Meter = 3.28 feet).