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<br />2.0 Precipitation and Snowpack Data <br />The two data sources used for this study are stations with long-term records in <br /> <br /> <br />precipitation operated by the National Weather Service (NWS) and in snowpack operated by the <br /> <br />Natural Resource Conservation Service (NRCS). National archives are held in Asheville, NC, <br /> <br /> <br />and Portland, OR respectively. For the precipitation data, we have applied further quality control <br /> <br /> <br />procedures which has resulted in some modified values so the archive now maintained at <br /> <br /> <br />Colorado State University in the Colorado Climate Center is not identical to the national archive. <br /> <br />Table 1 shows the stations with precipitation data along with the geographic location, elevation, <br /> <br /> <br />and starting year of the observation period. The snow sites are given in Table 2 with similar <br /> <br /> <br />information. A map of all the precipitation and snow sites is shown in Figure 2. The snow sites <br /> <br /> <br />are restricted to the higher elevations of the mountainous portion of the state while the <br /> <br /> <br />precipitation sites are located throughout the State at lower elevations. The highest elevation of a <br /> <br /> <br />precipitation site is 8,900 feet (Dillon). There are 24 sites included with records longer than 100 <br /> <br /> <br />years. The intent is to have enough long-term sites to be able to characterize drought back to the <br /> <br /> <br />beginning of the twentieth century for precipitation. Notice the snow measurements are not as <br /> <br />long. Most of the early observations were in the 1940s and 1950s. <br /> <br />Snow observations have not been quality controlled to the same extent as the precipitation <br /> <br />observations. Liquid-water content ofthe snowpack increases through the winter and almost <br /> <br />always past April 1. During April, the snow can continue to accumulate or it can start to melt. <br /> <br />While the April 1 snowpack is not the maximum, it is the last monthly observation which can be <br /> <br />used uniformly in the mountains. Consequently, only the April 1 observations will be used in this <br /> <br />study of dry and wet conditions. <br /> <br />4. <br />