The National Weather Service (NWS) issues various alerts to communicate potential marine hazards to communities along U.S. coastlines. These formalized communication tools provide timely information to protect life and property. Understanding the language of these forecasts is the first step in ensuring safety when living or traveling near the sea. The system includes different levels of severity, corresponding to the degree of threat posed by rising water levels. This tiered approach helps the public and local officials gauge the necessary response.
What Defines a Coastal Flood Statement
A Coastal Flood Statement (CFS) represents the lowest tier of formal coastal hazard alerts issued by the National Weather Service. This product is designed to inform the public about minor or nuisance flooding that is either occurring or highly likely to occur. The criteria for a CFS typically involve water level rise just above the threshold for minor flooding, usually resulting in inundation of less than one foot above ground level in vulnerable areas.
This type of flooding is often driven by non-severe weather factors, such as high astronomical tides, sometimes called “King Tides,” coinciding with minor wave action or persistent onshore breezes. The resulting saltwater intrusion is generally confined to the most exposed, low-lying coastal locations. These locations include waterfront parking lots, beach access points, docks, and the lowest sections of shore roads.
The Hierarchy of Coastal Flood Alerts
The NWS employs a standardized three-tiered system to categorize the severity and certainty of coastal flooding, which guides the public response. This system progresses from a Statement, which means to exercise caution, to a Watch, which means to be prepared, and finally to a Warning, which means to take immediate action. The Coastal Flood Statement signals the lowest level of concern, indicating that minor impacts are present or imminent.
Above the Statement is the Coastal Flood Watch, issued when conditions are favorable for significant coastal flooding to occur, but the exact timing or location remains uncertain. A Watch gives the public a lead time of roughly 12 to 48 hours to finalize preparation plans for a potential, more serious event. The highest level of alert is the Coastal Flood Warning, which is issued when life-threatening or substantial property-damaging flooding is imminent or already occurring.
A Warning means the hazard is certain and immediate, often involving significant beach erosion, destructive wave action, and inundation exceeding two feet in elevation. The distinction between these tiers is based on the predicted water level rise above normal astronomical tides and the associated potential for damage.
Navigating Impacts and Public Action
The impacts associated with a Coastal Flood Statement are generally minor and localized. Common consequences include standing saltwater on coastal roadways, which can temporarily limit access or reduce traffic speed, and minor beach erosion near the high tide line. Saltwater inundation can also affect coastal infrastructure like boat ramps, potentially corroding metal components over time.
Securing small, loose outdoor items in yards or on decks near the water is a prudent step to take when a CFS is in effect. Vehicle owners in low-lying areas, such as waterfront parking lots, should move their cars to higher ground to prevent damage from saltwater. The public should adhere to the universal safety rule: “Turn Around, Don’t Drown.” Driving or walking through floodwaters is dangerous due to hidden hazards, and just six inches of moving water can stall a passenger vehicle.