  Every year hundreds of people die at sea because of vessel and airplane
accidents. A key challenge in reducing the number of these fatalities is to
make Search and Rescue (SAR) algorithms more efficient. Here we address this
challenge by uncovering hidden TRansient Attracting Profiles (TRAPs) in
ocean-surface velocity data. Computable from a single velocity-field snapshot,
TRAPs act as short-term attractors for all floating objects. In three different
ocean field experiments, we show that TRAPs computed from measured as well as
modelled velocities attract deployed drifters and manikins emulating people
fallen in the water. TRAPs, which remain hidden to prior flow diagnostics, thus
provide critical information for hazard responses, such as SAR and oil spill
containment, and hence have the potential to save lives and limit environmental
disasters.
