Storm surge stands as one of the most perilous aspects of coastal storms, particularly hurricanes. It’s crucial to understand what storm surge is and how it differs from related terms like storm tide.
Storm surge is defined as the abnormal rise of seawater level during a storm. This rise is measured as the height of the water above the normal predicted astronomical tide. Essentially, storm surge is the excess water pushed inland by a storm’s powerful winds. Imagine the force of hurricane-strength winds relentlessly pushing against the ocean’s surface; this force is the primary driver behind storm surge. The water has nowhere to go but onshore, leading to significant coastal flooding.
To fully grasp storm surge, it’s important to distinguish it from storm tide. Storm tide represents the total observed seawater level during a storm. It’s the combination of the storm surge and the normal astronomical tide. Astronomical tides are the regular rise and fall of sea levels caused by the gravitational forces of the moon and sun. Therefore, if a storm surge occurs during a high astronomical tide, the resulting storm tide will be even higher, leading to more extensive flooding. The highest storm tides are frequently seen when storms coincide with new or full moons, as these are periods of higher astronomical tides.
The magnitude of a storm surge at any specific coastal location is influenced by several factors. These include the direction of the coastline relative to the storm’s path, the storm’s intensity, its size, its speed of movement, and the underwater topography of the coastal area, known as bathymetry. Areas with shallow coastal waters tend to experience higher storm surges because the shallow bottom restricts water flow, causing water to pile up onshore more easily.
Understanding “What Is Storm Surge” is vital for coastal communities. It’s not just about high winds; the overwhelming majority of fatalities during hurricanes are actually caused by drowning in storm surge. Recognizing the difference between storm surge and storm tide, and understanding the factors that influence storm surge height, are key to preparing for and mitigating the devastating impacts of these powerful coastal events.
