Extreme Water Levels from CO-OPS

Extremely high or low water levels at coastal locations are an important public concern and a factor in coastal hazard assessment, navigational safety, and ecosystem management.  The probability that water levels will exceed a given elevation is based on a statistical analysis of historical extremely high and low water levels.  This product provides annual exceedance probability levels for select Center for Operational Oceanographic Products and Services (CO-OPS) water level stations with at least 30 years of data.  When used in conjunction with real-time station data, exceedance probability levels can be used to evaluate current conditions and determine whether a rare event is occurring. This information may also be instrumental in planning for the possibility of dangerously high or low water events at a local level.

The extreme levels measured by the CO-OPS tide gauges during storms are called storm tides, which are the total observed seawater level during a storm, resulting from the combination of storm surge and the astronomical tide. They do not include wave runup, the movement of water up a slope. Therefore, the 1% annual exceedance probability levels do not necessarily correspond to the Base Flood Elevations (BFE) defined by the Federal Emergency Management Administration (FEMA), which are the basis for the National Flood Insurance Program. The 1% annual exceedance probability levels more closely correspond to FEMA's Still Water Flood Elevations (SWEL). The peak levels from tsunamis, which can cause high-frequency fluctuations at some locations, have not been included in this statistical analysis due to their infrequency during the periods of historic record.

Tags: acoustic sounders, alabama, alaska, american samoa, atlantic ocean, atmospheric/ocean indicators, bermuda, california, caribbean sea, center for operational oceanographic products and services, central pacific ocean, climate indicators, co-ops metadata library, coastal monitoring, coastal processes, coastal sea levelstations, coastal u.s. territories, coastal united states, compound extreme events, connecticut, continent, delaware, district of columbia, doc/noaa/nos/co-ops, earth science, extreme weather, flooding, florida, geomorphic landforms/processes, georgia, goes, guam, gulf of america, gulf of mexico, hawaii, hawaiian islands, johnston atoll, land surface, louisiana, maine, marine environment monitoring, marshall islands, maryland, massachusetts, micronesia, microwave water level (mwwl) sensor, midway atoll, mississippi, national ocean service, national water level observation network, new hampshire, new jersey, new york, noaa, noaa geostationary operational environmental satellites, north america, north atlantic ocean, north carolina, nwlon, nwlon station, ocean, oceans, oregon, pacific ocean, pennsylvania, physical oceanographic real-time system, ports, pressure sensors, puerto rico, rhode island, sea surface height, south carolina, storm surge, storm tide, texas, tidal height, tidal range, tide gauges, tides, tides and currents, u.s. department of commerce, united states of america, virgin islands, virginia, wake island, washington, water level gauges, water level predictions, western pacific ocean
Organization: National Oceanic and Atmospheric Administration, Department of Commerce