Because of recent West Virginia flooding deaths in the New River Valley (large drainage into narrow valley), you have been hired by FEMA to design a warning system, which could be activated at the first sign of river levels rising very quickly. Assume: 1) that the warning must be quick, so as to allow sufficient time for the residents to leave their homes and run/drive to higher ground, 2) many individuals will be inside their homes or other buildings, especially if the flooding occurs at night, 3) many residents are older with poor hearing. Indicate the which one sensory modality you will focus on, the key human factors principles involved with the appropriate/corresponding the design features, and then provide a final recommended solution.