SWELL WAVES

Swell waves are powerful waves generated by distant storms or strong winds, not by local winds. These storms transfer a huge amount of energy to the water, creating massive waves that can travel thousands of kilometres before reaching the shore.

• Distant storms, hurricanes, or strong gale-force winds create swell waves.
• They can travel vast distances, reaching coastlines far from the originating storm.
• Swell waves can reach significant heights, even exceeding 10 meters as witnessed in Kerala.
• Swell waves can cause coastal flooding and pose a danger to fishermen and beachgoers.

The Indian National Centre for Ocean Information Services (INCOIS) plays a crucial role in monitoring and predicting swell waves. Their Swell Surge Forecast System, launched in 2020, provides warnings up to seven days in advance, helping coastal communities prepare for these powerful waves.

Swell waves can have various effects, depending on their intensity, duration, and the area they impact.

Here are some common aftereffects:

• Coastal Erosion: Swell waves can erode coastlines, particularly if they coincide with high tides or storm surges. This erosion can lead to loss of land, damage to infrastructure, and changes to coastal ecosystems.

• Beach Nourishment: While intense swells can erode beaches, they can also deposit sand and sediment, leading to beach nourishment. This can be beneficial for coastal protection and tourism but may also alter the natural balance of the beach ecosystem.

• Damage to Coastal Structures: Swell waves can damage coastal structures such as piers, jetties, seawalls, and buildings located near the shore. Over time, repeated exposure to swell waves can weaken and deteriorate these structures.

• Navigation Disruptions: In harbors and coastal areas, swell waves can disrupt navigation by causing rough seas and hazardous conditions for ships and boats. This can lead to delays in maritime transportation and potential damage to vessels.

• Changes in Beach Morphology: Swell waves can reshape the morphology of beaches, altering sandbars, sand dunes, and shoreline contours. These changes can affect local ecosystems and recreational activities such as surfing.

• Ocean Currents and Upwelling: Intense swell waves can generate strong ocean currents and upwelling, bringing nutrient-rich waters to the surface. This can stimulate marine productivity and affect the distribution of marine species.

• Storm Surges: Swell waves associated with storms can cause storm surges, which are temporary increases in sea level along the coast. Storm surges can lead to coastal flooding, particularly in low-lying areas, causing damage to property and infrastructure.

• Long-Term Changes: Over time, repeated exposure to swell waves can cause long-term changes in coastal landscapes and ecosystems. These changes may include shifts in sediment transport, changes in habitat distribution, and alterations to coastal vegetation patterns.