However, the heaviest snow fall appears over. The 

 snow is expected to end over Alberta on Wednesday 

 ^November 2j. but continue over the remaining re- 

 gions." Snow was falling over North Dakota and north- 

 ern Minnesota, also. Winds were under the influence of 

 the deep low centered near Churchill, Manitoba. 



November 2.— While the high pressure area remained 

 centered over northern Yukon, an extension of this area 

 moved south along the Continental Divide and, within 

 this extension, a separate center was beginning to form 

 over western Wyoming, fig. 5. The low pressure area in 

 the vicinity of Churchill remained virtually stationary 

 but deepened further. The weather in the north con- 

 tinued to be under the influence of this deep low. Snow 

 continued to fall over most of Saskatchewan, Manitoba, 

 and Ontario. 



A secondary low pressure area, which had been de- 

 veloping over Arizona, New Mexico, and neighboring 

 states on November 1, began to deepen on November 2 

 and move rapidly northeastward along the cold front; it 

 reached southern Illinois by 12:30 P.M. and central 

 Illinois by 6:30 P.M. This low brought overcast con- 

 ditions, scattered snow showers, and strong winds to 

 the Middle West. In the Mississippi Flyway, the cold 

 front extended irl a southwest-northeast direction from 

 southern Missouri to north-central Ohio. 



November 3. —By November 3, the weather in the 

 southern part of the Mississippi Flyway was under the 

 influence of a strong high pressure area centered over 

 northeast Texas, fig. 6. With the clockwise flow of air 

 around the high, winds from the northwest occurred in 

 Iowa, Illinois, Missouri, Arkansas, and Mississippi. 

 Wind velocities in these states generally ranged from 15 

 to 20 miles per hour. 



The weather in the northern part of the flyway was 

 under the combined influence of the low that had been 

 over central Illinois on November 2, and that had moved 

 to the vicinity of Georgian Bay, Ontario, by 6:30 A.M. 

 on November 3, and of the high over northeast Texas. 

 This combination produced strong northwest winds 

 through Minnesota and Wisconsin. 



TEMPERATURE RANGE 



The average and minimum daily temperatures at 

 Winnipeg, Manitoba, from mid-October through November 

 10, 1955, are shown in fig. 7. There was a sharp de- 

 cline in temperature at Winnipeg on October 23 and 24, 

 followed by a pronounced warm wave on October 25 and 

 26. Temperatures started dropping on October 27. The 

 average temperature declined steadily from then until 

 November 3. The minimum temperature declined for 3 

 days, rose on October 30 and 31, and declined again on 

 November 1, 2, and 3. 



18 



DIRECTION, SPEED, AND ALTITUDE OF FLIGHT 



Observations on the 1955 mass migration of water- 

 fowl from the Great Plains of Canada into the Missis- 

 sippi Flyway of the United States yielded information 

 on direction or lines of flight, fig. 8, as well as on 

 speed and altitude of flight. Accounts of flights of 

 waterfowl over the Great Plains of Canada, the eastern 

 regions of North Dakota and South Dakota, western and 

 southern Minnesota, and parts of Wisconsin and Missouri 

 made it evident that long flights were made without the 

 benefit of landmarks provided by river systems. Never- 

 theless, concentrations of waterfowl observed following 

 river valleys made it clear that at times the birds used 

 river valleys as guide lines. 



Lines of Flight.— Especially large numbers of 

 waterfowl were observed following the Missouri River 

 valley from central North Dakota to northern Missouri. 

 One flight line apparently broke away from the Missouri 

 River above Pierre, South Dakota, where the river bends 

 sharply to the southeast, and crossed Nebraska to 

 reservoirs near North Platte. This assumption is based 

 upon a hiatus in the migration noticed to the west and 

 another to the east of the North Platte region in 

 Nebraska and upon the lack of migration immediately to 

 the west of the easternmost counties of Kansas. 



The flight of waterfowl following the Mississippi 

 River valley increased steadily in numbers as the birds 

 moved southward toward St. Louis, Missouri. Feeder 

 flight lines crossing Iowa and northern Missouri from 

 the northwest to the southeast added their ducks to the 

 main stem flight line. In migrating southeastward across 

 Iowa, waterfowl were observed following the valleys of 

 the Wapsipinicon and Des Moines rivers. 



Some flight lines moving southeast crossed the 

 Mississippi River and placed approximately 750,000 

 ducks in the Illinois River valley and western Indiana. 

 Small numbers of ducks moved into eastern Illinois and 

 western Indiana from due north. 



From St. Louis southward, the direction of move- 

 ment of the main flight line was due south. This flight 

 line did not at all times closely follow the channel of 

 the Mississippi River but spread out as much as 40 or 

 50 miles to the east or west of it. 



Small flight lines cut straight south over the Ozark 

 Mountains of southern Missouri. Some waterfowl utiliz- 

 ing these lines of flight probably stopped in the 

 Stuttgart, Arkansas, area, while others probably con- 

 tinued straight south into Louisiana. In central and 

 western Louisiana, flocks of waterfowl were observed 

 arriving from due north, indicating they had not followed 

 the Mississippi River flight line. 



Although waterfowl populations increased in 

 Michigan and Ohio as a result of this early November 



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