An aerial view of damaged buildings and washed-over land on the Bolivar Peninsula after Hurricane Ike.

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Preparing the 3D view

Preparing lighting and the first complete frame…

Model scale

Vertical dimensions ×1000. 100 km flat shelf. steady coastal setup.

Wind stress 1.65 Pa · imposed pressure drop 3000 Pa (30 hPa). Pressure-only rise 0.30 m.

How to read these results

Combined steady setup 1.10 m. The textured shore is a closed boundary, not mapped terrain; pale lines mark imposed onshore airflow. This excludes tides, waves and inundation and must not be used as a warning or flood forecast.

Storm surge

Explain how strong winds and low atmospheric pressure can raise coastal water levels, especially over a shallow shelf.

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Why it happens

Onshore winds push water towards the coast, while lower atmospheric pressure also raises the water surface. Shallow shelves can produce a larger setup for the same forcing.

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Bolivar Peninsula, Texas, September 2008. NOAA documented coastal damage from Hurricane Ike's storm surge.

Try a comparison

Set wind to zero and isolate a pressure drop of 3000 Pa. Combine the effects, then compare physical scale to discuss geometric scale.

Reading the result

This steady shelf experiment excludes tides, waves and inundation, which are needed to assess a real coastal flood.

A common misunderstanding

A hurricane’s wind category fully describes its coastal flood threat.

Coastal water rise also depends on storm size, track, duration, atmospheric pressure and the shape and depth of the coast. Tide, waves and river flow further affect flooding. A wind category therefore cannot specify the water level or inundation at a particular location.

Cases

Exam language

Storm surge

A rise in sea level above the expected tide, driven mainly by storm winds and atmospheric pressure. Coastal shape and water depth influence its size. Surge combines with tides and waves to determine coastal water levels and flooding.

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Bolivar Peninsula, Texas, September 2008. NOAA documented coastal damage from Hurricane Ike's storm surge.

Wind setup

A rise in water level where persistent wind pushes water towards a shore. It contributes to storm surge, particularly over shallow shelves and within bays. Its size depends on wind, duration, depth and coastal shape.

Inverse barometer

The tendency for sea level to rise where atmospheric pressure falls, and fall where pressure rises. A rough equilibrium estimate is about 1 cm per hectopascal. Storm surge also depends strongly on winds and coastal geometry.

Shelf

The shallow, gently sloping submerged edge of a continent, extending towards a steeper continental slope. Shelf depth and shape influence tides, waves and storm surge. A shallow shelf can support greater wind-driven water-level rise for the same forcing.

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NOAA South Atlantic bathymetry. Colour represents seafloor depth, revealing continental margins, abyssal basins and the Mid-Atlantic Ridge.

Tsunami

A series of long waves generated by rapid displacement of water, most commonly during a large undersea earthquake. In shallow water they slow and can grow in height. Tsunamis are not caused by the normal daily tides.

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Coastal damage after the 2011 Tōhoku tsunami. Run-up is the maximum vertical elevation reached by the water above a reference sea level; survey evidence is needed to attach a number to this photograph.

Still-water flood

Flooding described by the water level after short-period surface waves are averaged out. Coastal still-water level can include the tide and storm surge.

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The South Fork Stillaguamish River in flood. Water spreads beyond the usual channel when discharge exceeds channel capacity.

Barrier island

An elongated sandy island lying roughly parallel to the coast, separated from the mainland by a lagoon or other shallow water.

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Landsat observations of the Chandeleur barrier islands, Louisiana. Narrow sandy islands separate the Gulf of Mexico from shallow coastal waters; storm erosion can fragment and reshape them.

Adjust parameters

Onshore wind30 m/sShelf depth20 mPressure drop3000 Pa