When the incipient
foredune reaches a height of roughly 0.5 m (1.5 ft), the dune itself
becomes an obstacle to the wind. The dune continues to grow as wind-blown
sand from the beach is deposited on the dune. Vegetation such as
American beachgrass (Ammophila breviligulata) grows up
through the deposited sand to anchor the dune sand and cause further
Foredunes of 1-1.5 m
height (3-5 ft) may be tall enough to trap all the wind-blown sand
from the beach. At this point, inland dunes or structures do not
receive wind-blown sand from the beach.
the foredune closest to Lake Michigan is beginning to cut off the
sand supply to the larger inland foredune.
(Hoffmaster State Park in December 2003.)