One of the major rivers of Europe, the Elbeflows more than 1,000 kilometers across the continent before reaching the North Sea.
At its mouth, the low-lying landscape is continually reshaped by the rise and fall of the tides.
These dynamic tidal flats are a boon to biodiversity while sometimes posing challenges for those navigating its waters and for communities living along its shores.
The images above illustrate how the area changes with the tides.
They were acquired on August 15, 2025, at low tide and on May 11, 2025, at high tide with theOLI onLandsat 9.
The meantidal rangeat Cuxhaven is2.9 meters, which is considered intermediate, ormesotidal.
The tides are alsoasymmetrical, meaning the flood period is shorter than the ebb.
This causes the incoming current to run faster and typically carry more sediment up the 140-kilometer-long estuary than it does out.
The low tide exposes complex channels, sandbars, and mudflats around the river mouth.
This wide zone of coastal wetlands is part of the Wadden Sea, which stretches from the Netherlands to southern Denmark and represents the largest continuous system of intertidal sand and mud flats in the world.
Its habitats serve as important staging, molting, and wintering grounds for migratory birds, with more than 10 million passing through every year.
A channel cuts through these natural features near the river’s mouth, allowing ships to reach Cuxhaven and Hamburg—thethird-largestcontainer port in the European Union—farther upriver.
Dredging is required to remove accumulated sediment in the channel, andsome shipscan only pass through when the tide is high enough.
The Elbe’s mouth also provides access to the Kiel Canal, which connects the North Sea and Baltic Sea and is the world’s busiest human-made waterway navigable by seagoing ships.
At high tide, only a handful of small islands and sandbars remain above the waves.
One of these islands, Neuwerk, is a tranquil tourist destination that is home to a few dozen inhabitants and the oldest building on the German coast.
A brick tower, completed in 1310 and later converted to a lighthouse, was built to protect shipping on the Elbe from pirates andwreckers.
These images show normal tidal variation in the area, but storms can push water levels much higher than a typical high tide.
The highest water level measured at Cuxhaven—5.1 meters above Europe’s officialsea level reference—occurred on January 3, 1976, when a fast-moving storm swept across the North Sea and slammed the coast with high winds.
Researchers whoreconstructed historical stormsnoted that the storm surge was worsened by its timing relative to the tide.
The strongest winds arrived around low tide, preventing water that had propagated upstream at high tide from flowing back out to sea and causing further inundation inland.
Scientists study past extreme events like this to better understand how future storms might affect low-lying coastal areas and how flood protection could be improved.
Flooding risks can beexacerbatedby rising sea levels, which at Cuxhaven have trended upward by2.12 millimeters per year, or 0.70 feet per century.
Two new Earth-observing satellites are making it possible to measure water levels in coastal areas in greater detail.
The dual-band radar on theNISAR satellite is expected to track long-term phenomena such as sea level changes, as well as to mapflood inundationand other ephemeral events.
In addition, early data from NASA’sSWOT satellite has demonstrated the potential to accuratelymeasure water levelsaround complex coastlines and toimprove tidal models.
NASA Earth Observatory images by Lauren Dauphin, using Landsat data from theU.S. Geological Survey. Photoby Thomas Gölles. Story by Lindsey Doermann.
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Common Wadden Sea SecretariatWelcome to the Wadden Sea World Heritage. Accessed August 5, 2026.
EBSCO Research StartersElbe River. Accessed August 5, 2026.
Federal Maritime and Hydrographic AgencyTides. Accessed August 5, 2026.
Meyer, E.M.I. and Gaslikova, L.Investigation of historical severe storms and storm tides in the German Bight with century reanalysis data.
Natural Hazards and Earth System Sciences, 24, 481–499.
NASATides. Accessed August 5, 2026.
North Sea Region ProgrammeThe Elbe Estuary. Accessed August 5, 2026.
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