Fall and winter storms often develop quickly and tear away at the shorelines, removing sands from one place and depositing them elsewhere.
One survivor of this coastal erosion is the Old Harbor Life Saving Station. Now a maritime museum at Race Point Beach in Provincetown, it began life in 1897 twenty miles to the south on Chatham’s North Beach. In 1977, in the face of imminent destruction, the station was cut in half and floated on two barges to its present site.
During the summer, the beaches of the Outer Cape present a generally peaceful and benign aspect. A wide, gently sloping shelf of sand lies between the base of the sea cliffs and a rhythmic, moderate surf. The summer shoreline’s peaceful countenance encourages the illusion that all this change and rearrangement of shoreline lies in the settled past. There is little indication to the summer visitor of the ferocity, violence, and transformation that visit this coast in the “off-season.” But if one returns in late autumn, when the prevailing winds shift to the north and the east, when the first northeasters of the season begin to chew away at the wide summer beach, replacing it with a short, steep winter berm, one begins to have a sense that this is still a land in the making, that, as Henry Beston observed, “Creation is here and now.”
In winter the ocean storms claw into the base of these cliffs, undermining them. Along some stretches erosion is gradual, with little rivulets of sand running down the cliff face into the sea. At other places, especially where there are large deposits of clay, the process can be dramatic. Whole slabs of the marine scarp may shelve off at once, and a single stretch of cliff may lose 30 or 40 feet in one storm. In still other areas the beach appears to be accreting, with wide terraces of sand covered with beach grass building out from the cliff base. But overall the Outer Beach continues to erode, losing an average of three feet a year.
On the barrier beaches the erosion process is somewhat different, though the overall effect is also retreat. Barrier beach dune lines are dynamic systems. That is, they retreat and maintain themselves by moving with, rather than resisting, the ocean’s power. Normally the foreslopes of the dunes flatten out during a severe storm, presenting a less steep face to the waves, which helps to dissipate their force. Meanwhile wind and occasional storm surges that break through the line carry sand into the estuary or marsh behind the dunes. These deposits are gradually colonized by beach grass and other beach plants, which begin the process of building up another dune line as the foredunes continue to erode. Evidence of this gradual retreat can be observed by the occasional emergence in front of the present dune lines of peat ledges, the remains of a salt marsh or freshwater bog that once lay behind a former line of dunes. In a healthy system and under normal conditions a barrier beach “rolls over on itself” in a smooth progression landward.
On occasion, however, even this process is overwhelmed by an unusual manifestation of the sea’s power. One such manifestation was the Great Blizzard of February 6-7, 1978, called “The Storm of the Century.” Carrying 15-foot tides and hurricane-force winds, this storm rearranged many parts of the Cape’s shoreline. Monomoy Island, for example, was severed in two, and remains so today. But nowhere were the effects more dramatic and visible than at Eastham’s Coast Guard Beach. Storm surges breached the dune line, flattening 90 percent of the dunes themselves, carrying off most of the beach cottages, including Henry Beston’s Outermost House, and totally destroying the Seashore’s bathhouse and large parking lot.
Provincetown has always been the Cape community that has had to contend most with change. During the 19th century the moving dunes of the Province Lands threatened to bury its houses and silt up its vital harbor. Subsequent erosion control and beach grass plantings have so far kept the dunes at bay, but a more implacable force may now be threatening the town.
Over the past few decades oceanographers have observed an acceleration in the rate of sea-level rise, possibly the result of global warming. The sea may now be rising as much as one foot every century, which on low shorelines translates into a loss of 100 feet inland. Nowhere on Cape Cod does thick settlement lie so close to the shore as along the low, narrow streets of Provincetown. If present rises in the level of the sea continue, or, as seems likely, increase, the ocean may well claim this ancient fishing community before the dunes do.
Meanwhile the bulk of the Provincetown Hook continues to expand outward into the sea. The dangerous Peaked Hill Bars represent, in current oceanographic theory, the next ridge of Province Lands dunes in the making, rising gradually from the sea. But regardless of such gains, or the pains taken by humans to stem the loss of land from the sea, the Cape is inevitably losing more than it is replacing. Oceanographers estimate that for every five acres of shoreline lost to erosion, only two are replaced with new land in the form of barrier beaches or sand hooks. There is little doubt that the Cape’s ultimate fate is to return to the sea that spawned and shaped it. At current rates of sea-level rise, Cape Cod has at best only another five to six thousand years before the Puritan preacher Cotton Mather’s prediction comes true, and “shoals of codfish be seen swimming on its highest hills.”
