I grew up splitting time between New York and New Jersey, and up to 120 hours prior to landfall, all indications were that both of these regions would be seriously impacted regardless of the final track of Hurricane Sandy. My vantage point as an atmospheric scientist made me all too aware of the effects that a hurricane merging with a strong mid-latitude trough can bring to bear.
I knew coastal flooding was the major concern, with the storm approaching to coincide with the astronomical high tide. On top of that, Sandy generated swells in the 20- to 30-foot range.
Typically a hurricane gets steered out to sea by the jet stream when it tracks this far north. This time, however, with a strong high-pressure system providing blocking in the North Atlantic and the trough approaching the coast, these systems got close enough to merge near the coast, which strengthened Sandy right before landfall. The tilt of the trough pulled the storm westward directly at the coastline. This was the most damning part of the forecast, because the hurricane-force winds essentially piled the ocean up against the coastline all the way to landfall.
These three factors - astronomical high tide, direct hurricane impact, and fully developed seas - set the stage for historic flooding along the New Jersey coast. It was a worst-case scenario that came true.
On Sunday, I sat at my desk in Hawaii and watched the storm approach the East Coast, focusing on data from buoys, tide gauges and radar-estimated precipitation levels. Already water levels were reaching historic levels, even before the storm had turned west to slam into the coast. How high would it get?
A friend passed on an inundation map, which shows what land becomes submerged when water levels rise by a certain amount, and most of Cape May County and all the barrier islands along the coast were below the level of the projected storm surge.
A wise professor I had hated these maps because he said they don't tell the whole story and that we can build to withstand such advances in the water level. Well, he was right - kind of. Avalon and Stone Harbor have a very healthy, living dune system, complete with trees and plentiful dune grass to keep the sand in place. With an average height around 10 to 12 feet in the back dune, which rises to more than 40 feet in places, these dunes buffer the island from the full impact of the ocean.
As Sandy approached the coast on Monday, water levels at low tide were already above typical high tide due to the piling up of the water level from the storm winds. It wasn't looking good. Images started rolling into social-media sites of water rushing through neighboring island communities from the storm surge. The tides still had hours to rise, and the storm continued to approach with an anticipated landfall just north of Cape May County. But this was a blessing in disguise because the calm of the eye provided respite from the winds driving water up the beach and into the back bays, however short it was. Also, the front-right quadrant is climatologically the area of strongest winds, and thus the strongest surge potential was to the north of my home and much of Cape May County.
In the aftermath of the storm, several features appeared over and over. Huge amounts of sand washed into barrier island communities from their beaches, and homes were torn from their foundations by the storm surge that lasted hours. But none of this occurred in Avalon or Stone Harbor, only back-flooding from the bay that was enhanced by the rain. Yes, we were spared from the dreaded right-front quadrant of the storm but even Cape May saw this large surge of sand.
The one feature that separates Seven Mile Island from those that were devastated is the healthy dune system. Sure, some of these dunes were lost, but most still stand, as do the houses behind them.
I urge municipal and county planners to armor their coastlines naturally with a dune system full of trees, shrubs, and plentiful dune grass to hold the sand in place. Dunes are dynamic systems that grow and shrink, but they always buffer the full force of the ocean. Yes, oceanfront views will be lost, walks down to the beach may be longer as vegetation takes up more of the back-beach, and beaches may even become smaller as space is given over to planting dune grass. But what would you rather give up? Your house or your view?
Andre Pattantyus, a former Avalon resident now living in Hawaii, has his master's degree in meteorology and is studying toward his doctorate.