Weather and Estuaries

Hurricanes are one of the most severe types of weather. Hurricanes are intense tropical systems with very strong winds. The same storms in the Pacific Ocean are called typhoons. Hurricanes form over warm waters, where surface winds converge and the winds aloft are weak. They get energy from the warm waters and from the latent heat released as water vapor condenses into clouds. Hurricanes grow stronger as the air aloft moves outward, away from the storm center quicker than the air at the surface, as it moves toward the center. A hurricane will dissipate rapidly when it moves over colder water or a large land mass.

A Nor’easter is a type of winter storm that affects the Mid-Atlantic and New England states from September to April. These storms typically form within 100 miles of the coastline, anywhere from the waters of the Gulf of Mexico to the New Jersey coast and even over land.The storm gets its name from the strong northeasterly winds that blow in from the ocean ahead of the storm. Gale force winds (58 mph) are typical with a nor’easter, and more intense storms can have hurricane force winds (about 75 mph). Nor’easters impact one of the most densely populated areas of the US, from Washington D.C. to Boston. These storms produce high surf that cause coastal flooding and beach erosion, wind damage, and heavy rain and/or snow.

Tsunamis are a series of ocean waves generated by the displacement of the seafloor, either by earthquakes, underwater landslides, or volcanic activity. The waves from a tsunami may be only a few inches high in the deep ocean and can come ashore without causing damage. But in extreme cases, due to the severity of the displacement and bathymetry (topography of the ocean floor), the waves can increase in speed and height to become several meters high. When a significant tsunami comes ashore, it can destroy everything in its path - including coastal vegetation, mangroves, seagrass beds, and coral reefs. Tsunamis can scrape sediment off the ocean floor and deposit onto the land, and move invasive species into new areas.

Landslides are an on-going hazard that is related to coastal erosion. Storm systems can create large waves that weaken the flats at the base of coastal bluffs and steepen the face of the bluff. When combined with heavy rain, the land can give way, causing rock, soil and other related debris to crumble and slide down the face of the bluff.

Since 1900, the sea level has been steadily rising at an average rate of .07” per year and as more of the population moves and builds in these coastal communities, land subsidence (land sinking due to the added weight on the surface), even this small rise in the water can have huge localized impacts. Certain places along coastal locations, especially along the East Coast, have experienced an increase in the number of “nuisance flooding” events. Nuisance flooding occurs during normal high tides, and are not associated with storm surges. This type of flooding impacts roads, drainage systems and causes public inconvenience. Sea-level rise leads to the erosion of beaches and floods coastal ecosystems, eliminating wetlands and destroying the fragile balance of estuaries.