Benthonic Algae — SCAGEL 
525 
1953 NOVEMBER 
M 19 M 20 M 21 M 22 M 23 M 
with between 2-3 in. on the average falling 
during August in the Strait, and the maximum 
rainfall occurs in the winter, with between 
9-13 in. on the average in December. 
Near the entrance of the Strait, especially 
along the north side of Hope I., conditions of 
heavy surf generally prevail. Even when there 
is no sea a heavy swell is common. Farther 
down in the Strait to the south and east there 
is an area protected by scattered islands and 
reefs near the entrance, from the heavy swell 
from the open ocean, but this whole area is sub- 
ject to strong westerly winds in the summer 
months and to even stronger southeasterly winds 
during the winter months, so that the Strait is 
generally subjected to strong wave action and 
wind mixing. During the period mid-Septem- 
ber to mid-May the southeasterly winds are 
predominent and blow at speeds frequently up 
to 40 m.p.h. and occasionally higher. During 
the period mid-May to mid-September the west- 
erly winds predominate and blow at speeds up 
to 25 m.p.h. Particularly during this latter 
period, however, there may be considerable calm 
periods, especially during the morning hours, 
followed by strong seas which reach a peak 
about 1600 hrs. and then drop rapidly to rela- 
tive calm by 2000 hrs. 
Tidal Characteristics 
The tidal amplitude in the vicinity of Hope 
I. is usually about 17 ft. and the highest on 
record (37 years) was almost 19 ft. (December, 
1941). An extensive intertidal flora and fauna 
is exposed during low tide periods in this zone. 
Continuous tidal data are recorded since 1949 
at Alert Bay, near station 8 (Fig. 6). At the 
north end of Vancouver I. the tides are semi- 
diurnal and only moderately declinational, and 
thus springs and neaps are distinguishable ( Figs. 
