Swell scale

[Roberto]

I have found this scale for measuring swell, which I did not know

in the second column, the two addenda are respectively indicating wave length and wave height, as indicated below: ex State 4, A+M indicates A_verage wave length and M_oderate wave height

0 No swell
1, S or L, Very low
2, L + L, Low
3, S + M, Light
4, A + M, Moderate
5, L + M, Moderate rough
6, S + H, Rough
7, A + H, High
8, L + H, Very high
9, indef, Confused

Wave L_ength
S_hort <100m
A_verage 100-200
L_ong >200

Wave H_eight
L_ow >2m
M_oderate 2-4m
H_eavy >4m


is this one the scale used in the weather forecast, or is swell measured with the Douglas scale (which, referring to significant wave height seems less appropriate for swell and also more difficult to assess imho) ?



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[Twister_Ken]

AFAIK, UK inshore waters forecasts only use calm, slight, moderate, rough & very rough, but no scale. Of course, it's all a load of bullocks when the tide changes direction.



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[ubuysa]

I understand the Inshore Forecasts use the following (from the RYA book Weather At Sea):

calm - glassy 0m
calm - rippled 0m to 0.1m
smooth 0.1m to 0.5m
slight 0.5m to 1.25m
moderate 1.25m to 2.5m
rough 2.5m to 4m
very rough 4m to 6m
high 6m to 8m
very high 9m to 14m
phenomenal over 14m

Tony C.

<hr width=100% size=1>Eagles may soar, but weasels don't get sucked into jet engines.......

 

[Evadne]

There is, I believe a beaufort sea state to go with each of the wind strengths. This is rarely achieved in sheltered waters, but in oceanography and the offshore industry you will see claims like "DPSS operations in up to sea state 7" referred to, usually optimistically. To see what happens when it goes wrong, see the first half hour of "The Abyss"

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[dralex]

The Inshore Waters Forecast for Lyme Regis to Lands End used sea state "high" yesterday. I've never seen it in use before.


ps- what a great use for the word phenomenal.
<hr width=100% size=1>Life's too short- do it now./forums/images/icons/wink.gif<P ID="edit"><FONT SIZE=-1>Edited by dralex on 22/10/2004 15:22 (server time).</FONT></P>

 

[Roberto]

yep this is the Douglas scale for live sea state, I thought somebody devised a different scale for swell

alas the scale I indicated comes from some old notes of mine, cannot remember if it has any use (high seas weather report, oceanographic reports etc ?)


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[ChrisE]

I once got stuck in a 'high' sea in the Dover Straits for about 2 hours on the front of a rising severe gale/ wind over tide, not an experience I'm hurrying to repeat. Forecast went to 'very high' next day, so we abandonned our plans to continue

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