Laserfiche WebLink
<br />----_._--~- <br /> <br />-,...'" <br /> <br />reaches of the North Platte River and South Platte River <br />basins, the climate is semiarid and is characterized by warm <br />summers and mild to cold winters. <br /> <br />(2) Platte River basin. The climate of the Platte <br />River basin ranges from semiarid in the western portion to <br />subhumid in the area east of Grand Island. There are wide <br />variations in temperature and precipitation. The mean annual <br />temperature is 50 degrees, with recorded extremes of 117 degrees <br />above zero and 34 degrees below zero. <br /> <br />b. Precipitation. <br /> <br />(1) North Platte River and South Platte River basins. <br />PrecipitatiCJn in the two basins varies from more than 40 inches, <br />much of it snowfall in the higher elevations, to about 19 inches <br />in the plains areas of western Nebraska. In between, just east <br />of the mountains, average annual precipitation ranges from 12 to <br />16 inches. Along the South Platte River valley north and east of <br />the Denver metropolitan region to about the city of Sterling, <br />Colorado, the average annual precipitation is less 1;han 12 inches. <br />SUDDner cloudburst rainstorms are canmon, particularly in the <br />vicinity of Denver. <br /> <br />(2) Platte River basin. Average annual precipitation <br />in the Platte River basin varies from 20 inches in the vicinity <br />of North Platte to 28 inches near Plattsmouth, Nebraska at the <br />confluence of the Platte and Missouri Rivers. General rains, <br />intense local storms, and snowfall are typical of the Great <br />Plains midcontinent region. Seventy-five percent of the annual <br />precipitation occurs during the period April through September. <br />Spring storms, particularly those occurring in June, are often <br />intense and have, on occasion, produced as much as 16 inches of <br />rainfall in local areas within a period of 24 hours or less. <br />Runoff from rainfall has caused record flows, particularly in <br />the smaller drainages of the basin. Combinations of sno'Wll1elt, <br />severe local storms, and general rains, however, usually provide <br />conditions for the greatest volume and peak runoff" <br /> <br />c. Historical storms. <br /> <br />(1) South Platte River basin. Since 1884, 20 floods <br />are known to have occurred in the South Platte River basin. <br />Historical flood damages are not too meaningful, since signifi- <br />cant development within the basin did not take place until just <br />prior to World War II. Major urbanization of the Denver metro- <br />politan area began at that time, and extensive growth has been <br /> <br />6 <br /> <br />-~ <br />