EM 1110-2-1100 (Part II)
30 Apr 02
Figure II-8-8. Milepost map for use with Figure II-8-9; coastal distance intervals marked in nautical
miles (1 nautical mile = 1.9 km)
(d) The adjustment factor at the hurricane-prone oceanline reflects the difference in probability
distributions of hurricane wind speeds and wind speeds in other regions. Hurricane wind effects are assumed
to be negligible at distances of more than 100 miles inland from the oceanline. The adjustment factor can be
linearly interpolated between the oceanline and 100 miles inland. Some special wind regions are indicated
in Figure II-8-7. These regions could have considerably higher wind speeds than indicated in the figure. All
mountainous terrain and ocean promontories should be examined for unusual wind conditions. Figures II-8-8
and II-8-9 relate specifically to hurricane winds and are preferable for that application (Batts, Russell, and
Simui 1980). It is important to recognize that extreme wind speeds from these figures must be converted
from fastest mile to appropriate averaging time. Table II-8-7 provides relationships between fastest mile and
1-hr average wind speeds (also in Figure II-2-2). Averaging time adjustments, including conversion from
1-hr average to other averaging time, can be done using Table II-8-8, Figure II-2-1, or ACES.
II-8-18
Hydrodynamic Analysis and Design Conditions