Tidal effect on swell height/seas???

[Slabby20]

This is probably a stupid question but here goes anyway:

When planning a trip to fish offshore like at Nootka, Tofino, Barkley Sound....... what kind of tides do you look for? I've been told by a not so reliable source that bigger tide swings probably means bigger swells/seas but I have no idea if that's true. Also, how about moon phase? Any effect on swell size by the moon phase??

Thanks,
Slabby

 

[Karma-Kazi]

I usually look for offshore storms. this usually gives a good indication. But i am not educated in tidal or moon effects.

-Steve

 

[Rum Buddies]

swell is a result of a storm somewhere out in the deep blue, over distance the wind waves group in swells. Tide doesn't have any role in the size of swells. Tide will effect how the swell hits the land; certain spots surf better on lower or higher tides.

you can use this page to view a swell model: http://www.bigwavedave.ca/forecasts.php?page=6



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[Mucker]

I use the above page as well and it seems to be fairly acurate.

 

[Slabby20]

Thanks Poppa. That's a great site!! I agree that theres no question that storms and winds are the predominant factors on sea conditions. I just didn't know if the tides and moon phases play are part.

 

[bananas]

Big ebb tides out at swiftsure mean ugly water.Means an ugly ride out from bonila out.Once the tide slows and starts flooding you are good to go.

 

[Rum Buddies]

bananas is that due to the tide coming up against the wind waves or do you think it is tide bumping up against the swell that causes the bad water?



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[Charlie]

quote:Originally posted by Slabby20

This is probably a stupid question but here goes anyway:

Nope... No question is stupid!

quote:When planning a trip to fish offshore like at Nootka, Tofino, Barkley Sound....... what kind of tides do you look for? I've been told by a not so reliable source that bigger tide swings probably means bigger swells/seas but I have no idea if that's true.

I look for 5-8 foot tides, just my prefereance, but that is NOT "swells" or "sea state". Yes, take it to the "bank", as fas as "swells", but the bigger swells does not mean the biger the sea state?... the bigger the tide swing, which is effected by the moon does effect the size of the swells, usually storms effect the sea state! But it is NOT the size, as much as the interval? I am very okay, with having 18 foot swells @ 1 minute interval verses I would hate a 8 foot swell @ a 2 second interval? The closer the swells usually mean the higher the sea state, which equals "storm"! As the swells start spacing out... the storm has passed!

quote:Also, how about moon phase? Any effect on swell size by the moon phase??

Yes it does, but again... interval, interval,interval!
Google "swells verses "sea state", they are two different things?

 

[cuttlefish]

Good points all and way cool site there Poppa!
Wave intervals are influenced by currents. When a current is running with the wind wave or swell the interval is usually longer. When a current runs against the wind wave or swell the intervals get shorter and that's when things can get nasty as Charlie says. Of course wind waves and swells don't always come from the same direction and when mixed by a cross current, that's when things can get scary![xx(] Tidal currents are influenced by the tides and change four times a day. On big tides, during full and new moon phases the tides are highest and lowest and the tidal currents are strongest, having the most influence on wind wave and swell intervals. Tidal currents influence wind wave and swell intervals much more in near-shore areas. In offshore areas tidal currents slacken shortly after tide changes and then begin increase again in the opposite direction. So intervals may seem manageable only to change to unmanageable six hours later. When you get truly "offshore", tidal currents don't seem to have the same amount of influence but other currents like the Gulf Stream or storm generated currents will influence wave intervals.
Swell heights are also influenced by depth, peaking and even breaking over shoal waters found offshore. In my experience, the worst sea conditions are usually encountered early on the way out to the "offshore". Once out there things tend to spread out and become relatively organized but then once out there you have to get back in again.

 

[Tailspin]

Swiftsure or La Perouse Bank etc. can turn from 6' 12 seconds to 8' 7 seconds all in a tide change, with no change in wind speed. Makes a huge diffrence as Trevor said. The same applies for innshore stuff. Constance can go from a very tolerable ride to evil when it switches to an ebb on a 15kt Westerly. Each area also ebbs or floods from diffrent directions depending on the lunar Phase.

www.tailspincharters.com

 

[Rum Buddies]

what you guys are talking about is usually referred to as "period" and its basically the distance between wave peaks. you can view period models here:
http://magicseaweed.com/msw-surf-charts2.php?region=50&res=&type=period

Generally the bigger the period the more power behind a wave. If you were relating this to waves hitting the shore A 10' swell with a 6 sec. will be smaller a smaller "wave" then 6' swell with a 20 sec. period.

quote:the bigger the tide swing, which is effected by the moon does effect the size of the swells

Can you elaborate on this Charlie, I'm not sure I understand how the tide can effect the size of a swell?


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[Charlie]

quote:Originally posted by Poppa Swiss

the bigger the tide swing, which is effected by the moon does effect the size of the swells

quote:Can you elaborate on this Charlie, I'm not sure I understand how the tide can effect the size of a swell?

Sure I can!

quote:Originally posted by bananas

Big ebb tides out at swiftsure mean ugly water.Means an ugly ride out from bonila out.Once the tide slows and starts flooding you are good to go.

Bananas, would be VERY correct!

I have never had issues at Nootka, Tofino, or Barkley Sound? Most of the time offshore and in deep waters you really do not have to concern yourself with tides - in most areas, but there are exceptions to that. Guess what, The Strait of Juan de Fuca and Swiftsure Bank, are areas that are exceptions! You do need to concern yourself with the tides! And, they very much can affect the action of the swells and sea state in these areas!

Across the entire Strait it can get "nasty" from large tide changes partly due to the fact there is nothing out there to slow or change the water flow? Combine this with a large volume of outgoing water. Now think about how many directions and the force getting applied to the water at the entrance to the Strait and Swiftsure. The outgoing tide runs west. (The larger the tide change, the harder and faster the tidewater is moving.) The normal current is generally running south or southeast. The swells are usually moving east. Wind waves are either mostly from the west or south. These can make for some "very interesting" conditions and can make for a wet and miserable ride, on a nice sunny day! I have actually had 4/5 foot "walls" of water form on the east ends of the Strait, strickly from a big ebb tide!

I know everyone has been to Campbell River and witnessed the tide running? That is a whole lot of water running and it runs pretty fast, doesn't it? The bigger the tide change, the faster it runs! Looks just like a river? Now multiply that by the size of the Strait of Juan de Fuca, the San Juan's, and the entire Puget Sound! That water flows in and out twice a day. Twice a day it is flowing against the direction of the swells. During a full or new moon you have the bigger tide changes, creating more water flow, and the faster it runs! You have tremendous amount of water flowing against the swells, which will make them steeper and higher, especially in swallower waters. I have been out there when the tidal flow actually turned the swells into white caps and it can get miserable on a big ebb! Usually you turn out to sea – deeper water = calmer water, but that is when caught in a storm or whenever the weather turns to crap! However, if the weather is nice and you are in 2 or 3 foot white caps, check your tide. I relate it to "confused seas", even though I am not sure it falls into that classification? If caught in these conditions, I have found getting closer to shore is usually better?

Oh... There is a "Notice to Mariners" posted concerning hazardous wave conditions created by ebb tides on the east end of the Strait.