As the storm approaches and moves across he coastline, it brings huge surges, raising tidal sea levels 10 to 20 feet or more above normal. The rise may come rapidly and produce flash flooding of coastal lowlands, or may come in the form of giant waves. Hurricane storm tides do other types of damage. Flooding pollutes water supplies, cripples communications, shorts out power lines, causes sewers to back-up and overflow, undermines structures, and drastically revises shipping channels and shorelines. Torrential rains associated with hurricanes often cause widespread flooding, even after the storm has moved inland and has begun to die.
All hurricanes are dangerous, but some are more so than others.
The way storm surge, wind and other factors combine determines the hurricane s destructive power. To make comparisons easier and to make the predicted hazards of approaching hurricanes clearer to emergency forces, NOAA s hurricane forecasters use a disaster potential scale, which assigns storms to five categories. This is an awareness condition automatically set at this time of the year. Watch A planning condition indicating there is a hurricane in the Atlantic. A readiness condition indicating that a hurricane may strike the area that is forecasted.