An example computing system is configured to: (i) receive, from one or more sensors of a vehicle in motion over a body of water, a set of sensor data, (ii) based on the set of sensor data, determine (a) an instantaneous distance between the vehicle and a surface of the body of water and (b) an instantaneous slope of the surface of the body of water, (iii) based on at least one of the instantaneous distance or the instantaneous slope, determine a statistical representation of the surface of the body of water, and (iv) based on the determined statistical representation of the surface of the body of water, adjust one or more control surfaces of the vehicle to change one or more of a speed, altitude, heading, or attitude of the vehicle.