crest length The length of a wave along its crest. Sometimes called crest width.

cotidal Indicating equality with the tides or a coincidence with the time of high or low tide.

Communications Plan for the Tsunami Warning System in the Pacific Operations manual for the Tsunami Warning System in the Pacific. The Plan lists the tidal and seismological stations which participate in the warning system, preferred methods of communications between the stations and the Pacific Tsunami Warning Center (PTWC), and criteria for reporting. The Plan also lists recipients of tsunami watch and warning messages and methods by which the messages are sent. The Plan also provides a general overview of the operational procedures of the Tsunami Warning System and of the nature of tsunamis.