FLOOD08946 - Laserfiche WebLink

Home Browse Search

I -11- III. HYOROLOGY Moisture Sources There ~re three moisture sources available to the Gore Range.1,2.3,4 Each of these sources is associated with a different season of the year. Figure III-! illustrates the flow of air from these seasonal moisture Hydroloqic Records Hydrologic records (from precipitation and streamflow gages) in the mountainous areas of Colorado are of relatively good quality but have only short to intermediate recording periods. Due to the extreme orographic effects of the mountain barriers, however, the micro climate changes SO rapidly with elevation and from range to range that these records must often be supplemented with detailed analyses. Rainfall precipitation records are available .from the ~ational Weather Service (NWS) for stations at Dillon, Eagle, Climax and Bond. Short-term records have been kept by a CSU Atmospheric Science Department research group administered by Lewis D. Grant. Measurements have been taken by the research group at sites between Leadville and Minturn and at Vail Pass. four miles west of Vail Pass and two miles northwest of sources. Winter and spring snows, whiCh form the bulk of the annual precipi- tation are a result of moist air masses originating in the cool Northern Pacific Ocean in the Gulf of Alaska and moving inland from the Pacific Climax. , I I , , Northwest. These air masses must pass over the Cascade Range or the Sierra-Nevada Range, several ranges in Nevada, Idaho and Utah and then a series of ranges in the Colorado Rackies before arriving at the Gore Range. The series of up1ifts during transit causes much of the moisture to precipitate out, thereby limiting the amount of moisture available far delivery to the Gore Range. Summer showers and thunderstorms, with moisture pulled in from the Gulf of Mexico, occur most commonly in July and August, although thunderstorms can occur as early as May and as late as October. Tempera- tures in the Gore Creek Valley are usually too cold in May and June to provide the uplift necessary to produce significant thunderstorms and the showers that occur in the early months generally serve only to Snow precipitation records are taken at Shrine Pass and at Vail Pass stations by the S.C.S., in addition to the Forest Service and Vail Associates data at the Vail Ski Area site. Short-terrnsnowfal1 records were also collected along the highway by the C.S.U. researCh group. Streamflow records are kept by the U.S. Geological Survey (U.S.G.S.) far several of the streams within the Gore Creek catchment as well as in increase the snow pack moisture content. During the early fall (September and early October), there are occasional general rainstorms caused by dying major Pacific storms. These warm air masses, heavily loaded with moisture, move in from the San Diego area, passing through California. across Arizona and into nearby basins. Additionally. short-term data is available from a study for the Bureau of Reclamation on the meteorology of the Colorado River basin. This study provides data an both storm characteristics and rain- fall lasses (infiltration, detention and evaporation).