I live near the sea and was told that if we get a low pressure and a high tide we could be flooded, I would like to know how the air pressure affects the tides.
2006-10-02 04:52:03 · 6 answers · asked by sue l 4 in Science & Mathematics ➔ Weather
The low pressure means that the atmosphere is pressing on the sea less than usual. For every millibar that the atmospheric pressure falls, sea level rises by around 1cm. That means that if there is a serious low with a pressure of around 960 millibars then sealevels could rise by around 1/2 metre.
Low pressure also affects sea level by blowing more water onshore. This, along with the bulge in sea level due to the low pressure creates something called a storm surge. This is what caused the flooding in New Orleans during Hurricane Katrina - seriously low pressure led to the sea level bulging upwards and the strong winds piled the water up shorewards.
I'm guessing you might be east coast UK because they have just recently had very large tides. In the UK we thankfully don't get hurricanes meaning that storm surges are usually ok as they don't co-incide with high tide. However if you get a storm surge co-incide with high tide then it results in sea levels being much higher than they would normally be and coastal flooding.
The best example of this was 1953 when a deep depression caused a storm surge along the east coast and combined with a high tide. In the UK 307 people died, and in the Netherlands 1800. That scale of tragedy in the UK is unlikely now because of excellent forecasting, good communication etc, but the possibility for severe flooding still exists which was why the warnings were issued for the high tides over the past couple of months.
There's a whole load of more info on the 1953 flood and storm surges on the link below.
2006-10-02 08:53:10 · answer #1 · answered by oceanlass 2 · 0⤊ 0⤋
The air pressure does not effect the tides as they are always there. With low pressure you are likely to get strong winds which assist the tides to go farther up the beach than normal. Then you get sea water over the sea defences and across the road and then if the surrounding area is below sea level then the floods are there. On a weather map you can sea the combination of low pressure and winds as the isobars, lines of equal pressure. are very close together.
With high pressure the weather is settled and less windy.
2006-10-02 12:01:33 · answer #2 · answered by Anonymous · 0⤊ 0⤋
High air pressure moves towards low pressure. That is what creates wind. It doesn't affect the tides, I have never heard that theory before.
2006-10-02 12:34:42 · answer #3 · answered by bird brain 2 · 0⤊ 0⤋
basically.. if there is low air pressure in your region, and high pressure somewhere else, the water being pressed on (where there is high pressure) needs to go somewhere. if in your region there is low pressure the water will find it easyer to rise therefore creating a rise in the water level. when all of this is enhanced by a high tide (caused mostly by the gravitational pull of the moon) it could cause a flood in extreme cases.
2006-10-02 12:07:46 · answer #4 · answered by ^^orion^^ 1 · 0⤊ 0⤋
If the pressure is low it will allow the water to raise. If it is high it wont raise as far.
2006-10-02 12:00:36 · answer #5 · answered by David T 3 · 0⤊ 0⤋
low pressure brings in rain and clouds so more water
2006-10-02 11:57:57 · answer #6 · answered by RAMSBOTTOM 5 · 0⤊ 0⤋