The wave climate at a particular beach also détermines the effect
a storm will hâve. In a high-energy climate, storm waves are not much
larger than ordinary waves, and their effects may not be significant. An
example of this might be northeasters occurring at Cape Cod. In a lowenergy wave climate, where transport volumes are usually low, storm waves
can move significant amounts of sand, as do hurricanes on the gulf coast.
The type of beach sédiment is also important in storm-induced changes
A storm can uncover sédiments not ordinarily exposed to wave action, and
thus alter the processes that follow the storm. (Morgan, et al., 1958.)
In sand-deficient areas where the beach is underlain by mud, the effects
of a storm can be severe and permanent.
The effects of particular storms on certain beaches are described in
the following paragraphs. These examples illustrate how an extreme event
may affect the beach.
In October 1963, the worst storm in the memory of the Eskimo people
occurred over an ice-free part of the Arctic Océan, and attacked the coast
near Barrow, Alaska. (Hume and Schalk, 1967.) Detailed measurements of
some of the key Coastal areas had been made just before the storm. Freeze
up just after the storm preserved the changes to the beach until surveys
could be made the following July. Most of the beaches accreted 1 to 2
feet, although Point Barrow was tumed into an island. According to Hume
and Schalk, "The storm of 1963 would appear to hâve added to the Point the
sédiment of at least 20 years of normal longshore transport.” Because of
the low-energy wave climate and the short season in which littoral processes can occur at Barrow, this storm significantly modified the beach.
A study of two hurricanes, Caria (1961) and Cindy (1963), was made by
Hayes (1967). He concluded that "the importance of catastrophic storms
as sédiment movers cannot be over-emphasized,” and observed that, in lowenerg) v.ave climates, most of the total energy is expended in the nearshore zone as a sériés of catastrophes. In this région, however, the rare
extreme” hurricane is probably not as significant in making net changes
as the more frequent moderate hurricanes.
Surprisingly, Hurricane Camille, with maximum winds of 200 mph, did
not cause significant changes to the beaches of Mississippi and Louisiana.
lanner (1970) estimated that the sand transport along the beach appeared
aye een an amount equal to less than a year’s amount under ordinary
conditions, and theorized that "the particular configuration of beach, sea
, an Coastal ridge tended to suppress large scale transport.”
The
S5ruck.the “este™ coast
Louisiana in June, 1957.
However rh» °. ° eaci during the storm were not extreme nor permanent,
cient Ind ®
eXp°Sed marsh sediments in areas where sand was defiin„ the^torT" >' Stage f°T a period of raPid shoreline retreat followretonsibîe^r a'°rgan’ et al’> 19S8-) Indirectly, then, the storm was
responsible for significant geomorphic change
4-38
a storm will hâve. In a high-energy climate, storm waves are not much
larger than ordinary waves, and their effects may not be significant. An
example of this might be northeasters occurring at Cape Cod. In a lowenergy wave climate, where transport volumes are usually low, storm waves
can move significant amounts of sand, as do hurricanes on the gulf coast.
The type of beach sédiment is also important in storm-induced changes
A storm can uncover sédiments not ordinarily exposed to wave action, and
thus alter the processes that follow the storm. (Morgan, et al., 1958.)
In sand-deficient areas where the beach is underlain by mud, the effects
of a storm can be severe and permanent.
The effects of particular storms on certain beaches are described in
the following paragraphs. These examples illustrate how an extreme event
may affect the beach.
In October 1963, the worst storm in the memory of the Eskimo people
occurred over an ice-free part of the Arctic Océan, and attacked the coast
near Barrow, Alaska. (Hume and Schalk, 1967.) Detailed measurements of
some of the key Coastal areas had been made just before the storm. Freeze
up just after the storm preserved the changes to the beach until surveys
could be made the following July. Most of the beaches accreted 1 to 2
feet, although Point Barrow was tumed into an island. According to Hume
and Schalk, "The storm of 1963 would appear to hâve added to the Point the
sédiment of at least 20 years of normal longshore transport.” Because of
the low-energy wave climate and the short season in which littoral processes can occur at Barrow, this storm significantly modified the beach.
A study of two hurricanes, Caria (1961) and Cindy (1963), was made by
Hayes (1967). He concluded that "the importance of catastrophic storms
as sédiment movers cannot be over-emphasized,” and observed that, in lowenerg) v.ave climates, most of the total energy is expended in the nearshore zone as a sériés of catastrophes. In this région, however, the rare
extreme” hurricane is probably not as significant in making net changes
as the more frequent moderate hurricanes.
Surprisingly, Hurricane Camille, with maximum winds of 200 mph, did
not cause significant changes to the beaches of Mississippi and Louisiana.
lanner (1970) estimated that the sand transport along the beach appeared
aye een an amount equal to less than a year’s amount under ordinary
conditions, and theorized that "the particular configuration of beach, sea
, an Coastal ridge tended to suppress large scale transport.”
The
S5ruck.the “este™ coast
Louisiana in June, 1957.
However rh» °. ° eaci during the storm were not extreme nor permanent,
cient Ind ®
eXp°Sed marsh sediments in areas where sand was defiin„ the^torT" >' Stage f°T a period of raPid shoreline retreat followretonsibîe^r a'°rgan’ et al’> 19S8-) Indirectly, then, the storm was
responsible for significant geomorphic change
4-38