Video and print story at WECT TV, Wilmington.  

Star News story with slide show.

NC Sea Grant press release.  It has a link to a pdf on Exploring Rip Currents.  A bit of that pdf (my emphasis):

"Most rip current research has been conducted on large-wave beaches with natural features that produce fast, fixed rip currents that can be studied almost any day.

The rip current hazards on the Atlantic and Gulf coasts are smaller features, often much more ephemeral and much harder to predict. Little previous research has been conducted on those beaches to determine the frequency, velocity and circulation that would threaten potential victims. 

The most dangerous rip currents on any particular North Carolina beach typically occur only 5 to 10 swimming days each year and are difficult to predict days in advance."

BTW, Rob Brander would still like to get Americans to respond to his rip current survivor survey, which is linked at the Melbourne (Fla.) National Weather Service, and here.  

UNCW graduate student, Cobi Christiansen deploys a drifter. Photo by Spencer Rogers.  (NC Sea Grant)