602 
Journal of Agricultural Research 
Vol. XXX, No. 7 
The Victoria and San Francisco 
stations are in exposed situations and 
record more of the prevailing winds 
of the coast. The Vancouver and 
Roseburg Stations are in more sheltered 
situations and, consequently, record 
less of the prevailing winds. The 
latter do, however, give a good record 
of local and surface winds. 
Anemometer records, as well as the 
recorded observations of many weather 
bureau observers, show that the Strait 
of Georgia, Washington Sound, and 
Puget Sound form a very favorable 
channel for the movement of a wide 
current of air from the northwest 
down into the interior and south¬ 
western part of Washington. There 
are periods of one to several days with 
continuous northerly winds. Between 
May 26 and June 26, 1922, the Seattle 
records show that there were three 
such periods with winds, as follows: 
N. 
NE. 
E. 
SE. 
S. 
sw. 
W. 
NW. 
May 26-31_ 
502 
207 
186 
60 
June 15-18_ _ 
227 
298 
3 
6 
89 
143 
June 23-26_ 
321 
82 
3 
70 
200 
The continuity of the surface winds 
is interrupted by cross currents caused 
by mountains and valleys below, and 
by countercurrents in the upper atmos¬ 
phere. The valley of the Columbia 
River causes particularly strong cur¬ 
rents to the east or west. Pilot balloon 
records at Camp Lewis, Wash., show 
that for June, 1922, the direction of the 
prevailing winds at the surface was 
northwest and that above 1,500 feet 
elevation the prevailing direction was 
southwest. Rarely would it be pos¬ 
sible for the same body of air to move 
from the Strait of Georgia across Wash¬ 
ington into Oregon. There was, how¬ 
ever, one brief period, June 16 and 17, 
1922, when this might have occurred. 
During these two days there were 502 
miles of northerly wind at Seattle, 
Wash., and 453 miles at Portland, 
Oreg. The pilot balloon at Camp 
Lewis showed for June 17 a continuous 
north wind up to an elevation of 5,000 
feet. 
In a similar manner the air moves 
southward over western Oregon, es¬ 
pecially along the Willamette Valleys 
into southern Oregon and northern 
California. Although there are more 
intervening valleys and mountains here 
than in the north, their influence is 
offset by the relatively greater number 
of north winds. 
Between the Cascades and the Rocky 
Mountains, wind movements are simi¬ 
lar to those west of the Cascades. The 
anemometer records for Summerland, 
B. C. (Table XI) may be taken as 
fairly representative for the valleys 
which extend north and south in the 
interior and southeastern part of British 
Columbia. Observations made twice 
each day at Nelson, B. C., give the 
frequency of the winds at that station 
for 1922 as follows: 
! 
f 
Total 
Direction 
N. 
NE. 
E. 
SE. 
S. 
SW. 
W. 
NW. 
Calm 
observa¬ 
tions 
May._ 
1 
7 
4 
12 
1 
5 
8 
17 
7 
62 
June.:_ 
4 
2 
2 
6 
1 
2 
! 
12 
16 
15 
! 
60 
Although there are no anemometer 
records for northeastern Washington 
and northern Idaho, the eye observa¬ 
tions by meteorologists in that part 
of the country indicate considerable 
northerly wind in the north and south 
valleys. There is probably as much 
northerly wind at any one place in 
these valleys as in Puget Sound. 
They are, however, relatively narrow. 
The country is more broken, and the 
daily range of the temperature is 
greater. These factors all tend to 
break the continuity of air currents 
and make it improbable that they 
can flow continuously in the interior 
as far as they do along the Strait of 
Georgia and Puget Sound. It should 
be noted that Summerland is in the 
dry country between the white pine 
belts and that there is a greater amount 
of northerly wind in the dry belt than 
in country farther east. The con¬ 
tinuity of northerly winds down the 
Arrow Lake Valley is broken by cross 
currents at Nelson. 
