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. IV. DESCRIPTION OF THE FLOODS OF JUNE 1965 16. METEOROLOGY During the'period ot 15-18 June 1965, a quasi-stationary tront was oriented on a north-south line alons the mountains in southern WYCllllins, Colorado, and northern N_ Mexico. On 14 June, a closed circulation tomed aloft over the Calitornia-Nevada area and continued to deepen, therebT causing southerly winds over Colorado. This upper air low, coupled with a ridge over the Great Plains region, produced an atmospheric circulation that transported a deep layer ot JIIOist air northward trCIIII the Gult ot Mexico to the plains east ot the Rocky Mountains. At the SUle time, a series ot squall lines tormed and moved rapidly eastward trQIll the quasi-stationary tront, triggering intense precipitation in various locations east ot the mountains. The surtace dewpoint temperatures during this period were generallY in the upper 50's. On 18-19 June the upper air low began dissipating, allowing the upper-air wind circulation to return to a JIIOre westerly direction over Colorado. The quasi-stationary tront then began to DlOve eastward out ot the tlood area as a cold tront. ' 17. DEPTH-.AlIEA-DURATION VALUES The rainfall iso~tallll&p ot the stom, plate 2, and the raintall depth-area curves, plate 3, illustrate that the .t01'lll ot 16-17 June 1965 ranks with the maJor .t01'lllS tor this general area. The iso~talmap and pertinent depth-area values were derived trCIIII the regular Weather Bureau precipitation station records tor this area, and trCIIII "bucket survey" data obtained shortly atter the storm bT survey teas trCIIII the Corps ot Engineers and the Bureau ot Rec18Jll&tion. Plate 4 illustrates the 6-hour stomdepth-area amounta on 16 and 17 June tor the portion ot the storm in the Denver-Colorado Sprinss area and, tor clllllparison, the 6-hour probable llUlXimum storm values and the 6-hour values tor the 30-31 ~ 1935 stom. Relative atom magnitudes are self-evident. 18. STORM PATTElllIS Antecedent raintall prior to the principal stom was moderate and apotty. The tloods which occurred in the South Platte River baain during the period 14-22 June 1965, resulted trail. heavy to torrential raintall over large portions ot the South P1&1;te River basin. Heavy raintall occurred over portions ot the northern sections ot the South Platte River baain on the 14th and 15th ot June. As the storm system moved southward, torrential raintall centered principally over the Plum Creek and BiJou Creek watersheds on 16 June. 8to1'lll raintall on 16 June extended over sClllle 3,000 square miles ot the South Platte River basin, including the Plum Creek, Cherry Creek, and Sand and Toll Gate Creek watersheds in the Denver region, and,the Kiowa Creek, COIIIJIIanche Creek, Badger Creek, and Beaver Creek watersheds to the east. 10 .