Surf Glossary: D

Deep Water
Water deep enough so that surface waves are not affected by the bathymetry on the ocean bottom. Generally, water more than 1,000 feet, or at least deeper than one-half the wavelength of the existing waves is considered deep water.

Deepwater Breaks
Surf spots where the swells have a steep transition from deep water to shallow water so the waves are generally bigger and more powerful than elsewhere. Also includes surf spots where the deep water bathymetry of the ocean floor can greatly focus longer period swells (over 16 seconds) to create larger and more powerful waves. Spots with underwater canyons like Blacks are a prime example.

Degrees
A) The unit of measurement for direction to analyze where wind and swell direction is coming from. North is 0 or 360 degrees (12:00 o'clock); and then moving clockwise, east at 90 degrees (3:00 o'clock), south at 180 degrees (6:00 o'clock) and west at 270 degrees (9:00 o'clock). Northeast may be anywhere between 0 and 90 degrees, southeast between 90 and 180 degrees, southwest between 180 and 270 degrees and northwest between 270 and 360 degrees. B) Degrees also are used to measure Latitude and Longitude, with minutes and seconds used a fractionals between the degrees. One degree of Latitude will always equal 60 miles at that same location. One degree of Longitude will always vary due to the curvature of the Earth toward the poles.

Diffraction
The process of wave energy filtering into the lee of obstacles such as breakwaters by the transfer of the wave energy along wave crests. Diffracted waves are smaller than the original waves.

Direction
Where the wind or swell is coming from. In the marine community, directions are always identified as the direction the swell or the wind is "coming from," not the direction it's headed.

Double Up
When two waves combine, often creating an extra powerful wave with twice the amount of energy. Double up waves often create the best waves to get barreled or tubed on because the interaction of the waves forces the waves to break in shallower water than normal, which creates hollower, steeper waves.

Down-the-line
A reference to the direction further along the crest of a wave from the location from where a surfer drops into the wave. The direction toward which the surfer is riding. Waves can also be described as "down-the-line" when the wall is long and fast.

Dumping
Used to describe waves that are very hollow and hard-breaking.

Duration
In wave forecasting, the length of time the wind blows in the same direction over the swell generating area, or the fetch. Duration is one of the three key elements in the fundamental wave generation formula-along with wind velocity and fetch length-used to determine wave heights and wave periods in a storm or wave generating area.

Surf Glossary: C

Caught Inside
A circumstance in which a surfer is trapped between the shoreline and breaking waves. This usually means the surfer will have to wait for a lull between the larger breaking waves for a chance to slip into clear water.

Central Pressure Index (CPI)
The minimum atmospheric pressure in the eye or center of a hurricane, which is used to estimate the wind velocities in the storm. The lower the CPI, the faster the wind speeds.

Choppy
Bumpy ocean and wave conditions that are rough due to strong winds and/or currents. Wind velocities are usually over 12 knots to create choppy conditions.

Clean
Good surfing conditions with decent wave energy, a smooth or glassy ocean surface and very little onshore wind. Offshore winds blowing into the faces of the waves can create clean, groomed conditions.

Clean-up Set
A much larger wave or a set of waves, which breaks further outside than normal. A clean-up set usually "cleans" the line-up of surfers caught further inside.

Closeout
When all parts of the wave-down the line or crest of the wave-break at the same time. (Opposite of closeouts, the ideal waves for surfing are ones that break from one side to the other so the surfer can angle across the face of the wave.)

Combo Swell
A combination of swells from varying directions, which will create peaky and crossed up conditions as the waves merge together. Combo swells are great for most beachbreaks but break up the perfect lines at most reef and point breaks.

Consistent
A surf condition when waves are coming in very frequently and in predictable quantities.

Continental Shelf
The underwater shelf extending from a continent out to sea to a depth of about 165 fathoms or 1,000 feet. Long period swells of about 20 seconds will begin to feel the ocean floor at about 1,000 feet.

Contour
A line on a map or chart representing points of equal value compared to datum or starting point. An isobath is a line connecting points of equal depth below a datum to measure bathymetry, and an isobar when used to represent atmospheric pressure.

Corduroy
Describes the vision of a series of swells marching in from the horizon.

Corners
The end sections or shoulders of waves. A term usually used on the more closed out days when surfers try to find shoulders or corners to ride.

Crest
The top part or lip of the wave or swell.

Curl
Older term used to describe the concave face of the wave just before breaking; the area just before the barrel. ("Shoot the curl" was a popular longboard expression from the '60s.)

Cyclone
An atmospheric closed circulation rotating counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.