“Beaches, dunes, and barrier islands must move, or they die. We humans think we must stop beaches from moving or we will die. Or, at the very least, loose our possessions and imperil our fortunes.”
The BEACH: A History of Paradise on Earth, by Lena Lencek & Gideon Bosker
Had enough of winter coastal storms yet? Been to the beach? I’m five decades now of knowing a specific Jersey beach, and actually always loved it more in winter, because I love a good storm and the raw power of the sea whilst being comfortably on land. Nothing in this world beats walking out onto an open beach in a raw winter gale, where the surf thunder and scent of the sea and beach is echoing in your ears shoved up your nostrils in an invigorating blast, then sitting in front of a fire as you warm back up, with good wine as the storm rattles the storm windows. I recently was searching some old records and came across this little gem that I filed a few years ago, but sure still applies, from the ASPBA (American Shore & Beach Preservation Association):
A wide, sandy beach is best suited to stand up to a storm’s onslaught, offering better protection for upland homes, habitat and infrastructure. When a nor’easter, tropical storm or hurricane approaches, most people along the coast know the best thing to have between them and the waves is a wide, sandy beach.
It only makes sense…. but what’s really behind a beach’s storm protection benefits?
QUESTION: Do better beaches equal better storm protection?
ANSWER: Yes. Numerous studies have shown that wide, sandy beaches protect upland property better than narrow, sand-starved ones. The reasons are obvious: The beach and near shore sandbar system are your first lines of defense when a severe storm approaches. The more distance between crashing waves and upland trees, roads and buildings, the better the chances that those destructive waves won’t come crashing down (or washing through) the habitat or infrastructure you’re hoping to protect. A wide beach works like a speed bump for storm waves, forcing the approaching waves to break and expend their energy farther seaward of upland property.
QUESTION: What does a healthy beach do to counteract the rising tide of a storm?
ANSWER: A healthy beach is not just wider, it usually is also higher (meaning the “dry” beach above the high-water area) and has a functioning dune system (mounded sand above the active surf zone that’s been shaped by wind and waves). Both elements come in handy when incoming storms push water levels higher (what’s known as a storm surge) thanks to a combination of high winds and surf associated with storms and the forward motion of the storm system. These surges can pile on additional feet of water in addition to the usual tidal surge and the wind-whipped waves, posing a higher flood risk to low-lying areas near the coast. While a healthy high beach and an established dune system may not completely stop this increased influx of water, it can certainly slow it down or lessen the flooding that could result.
QUESTION: Will a beach change as the result of an approaching storm?
ANSWER: Yes, often quite dramatically. Since waves, wind and tidal currents shape beaches day in and day out, the stronger forces that a storm brings to bear can produce more dynamic results. The gentle (also called longer period) waves of summer tend to build the beach by transporting sand onto the beach. The short-period waves associated with storm transport sand offshore due to their greater energy and scouring force. Higher storm waves and tides also reshape the beach profile on both the “wet” and “dry” beach, often creating a flatter beach as fore dunes are cut down and offshore sand is pushed landward. Once the storm passes, a return to traditional wind and wave patterns brings back the longer period waves that will transport the sand pushed offshore back onto the beach, rebuilding the high tide beach and eventually the dunes.
QUESTION: In lieu of a wide healthy beach, how do other beach protection efforts fare during storms?
ANSWER: The returns are mixed. Seawalls provide protection against rising storm waves and surge, but many can fail when faced with the strength and scour of storm waves if they are not properly designed.
Rocks and rip-rap dissipate incoming wave energy, but usually don’t offer the distance or height needed to withstand the storm’s surge and protect the uplands… and rip-rap may eventually cause the recreational beach to disappear when sand erodes seaward of these structures. Sand-trapping devices that try to capture sediment in day-to-day winds and waves simply can’t be designed to withstand the destructive force of an approaching storm. Experience has proven that nothing works as well as a wide sandy beach, one that puts distance and height between waves/tides and the upland infrastructure, to provide storm protection.
QUESTION: If the beach has been re-nourished, does that mean it’s safe to stay and ride out a storm?
ANSWER: No. Beach projects are designed for average conditions,not the extraordinary strength storms may contain. A wide nourished beach may mean beach homes, roads and utilities have abetter chance to survive the storm,and that flooding will be lessened or of a shorter duration. But it doesn’t change the potential for wind damage to structures, trees and infrastructure; the loss of essential services during the storm; and the time it may take to restore those services afterward. In the case of major hurricanes, flood levels may also exceed the elevation of the protective beach. Calling for a storm evacuation is not taken lightly by the officials responsible for that decision; your decision on whether to stay or go should be made with equal seriousness.
For more information, asbpa. org.