National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
NOUS41 KGYX 212215
PNSGYX
PUBLIC INFORMATION STATEMENT...NATIONAL SAFE BOATING WEEK

NATIONAL WEATHER SERVICE GRAY ME

615 PM EDT TUE MAY 21 2013



...THE NATIONAL WEATHER SERVICE and NERACOOS (NORTHEASTERN REGIONAL ASSOCIATION

OF COASTAL OCEAN OBSERVING SYSTEMS) CONTINUES TO OBSERVE MAY 18th

THROUGH 24TH AS NATIONAL SAFE BOATING WEEK...



...Wind and Waves...



The following is a safe boating message from the National Safe Boating Council

and the National Weather Service...reminding you that National Safe Boating Week

is May 18TH through May 24th.



National statistics in 2011 indicated that 377 boats went down in calm seas

nationally.  However...287 crafts also sunk under choppy...rouch or very rough

conditions during this period.



Wind and waves affect all types of boats so it is important all boaters know

some basic facts about winds and waves. Wind over water is usually stronger

than over nearby land. Wind is the main factor in wave development and in general...

the stronger the wind...the larger the waves.



Individual waves are measured from trough to crest. Seas are the combination of

both locally generated wind waves and distantly generated swell waves and are

expressed in the terms of the Significant-Wave-Height...The mean or average height

of the highest one third of the waves. It approximates the value an experienced

observer would report if visually estimating sea height. When expressed as a range

(for example...seas 3 TO 5 ft)...this indicates a degree of uncertainty in the

forecast and/or expected changing conditions. The danger presented to a vessel is

a function of wave steepness as well as wave height and is unique to each vessel.

In general for small vessels...for a given wave height the danger increases as the

wave period decreases.



"The seventh wave of the seventh set"...An old fisherman`s tale? Perhaps...but it

does serve to highlight that wave and surf conditions are not always constant.

In open waters...the occasional wave may be twice that of the surrounding sea.

There are occasional reports of "rogue" waves of an even greater ratio. Near

shore...waves are even less predictable. So-called "sneaker waves" can grab the

unwary who venture too close to the unpredictable sea. Mariners may be drawn too

close to the surf zone during periods of relative calm. Proceed cautiously and

always be wary of this not uncommon phenomenon...especially in areas where breaking

surf is known to occur or appears likely.



Winds and waves can change quickly in speed...direction and steepness so it is

important you include a marine forecast in your preparations for boating.



This message from the National Safe Boating Council was forwarded to you by the

National Weather Service and the Northeast Regional Ocean Observing

System...NERACOOS.