Evacuation inland ("horizontal evacuation") is the traditional method of saving life in areas forecast as the site of hurricane landfall. But “high confidence”; warning time is only 12 hours, while some coastal areas are now so densely populated that twice that time is required for evacuation. Coastal managers must therefore risk the ire of local citizens “unnecessarily”; evacuated early, and the associated risk that several false alarms will reduce citizen compliance,orthe risk that evacuation will be too long delayed.