Precipitation and drought effects are not evenly distributed in Nevada. The graph below (from the Natural Resources Conservation Service's SNOTeL sites in northeastern Nevada, for the upper Humboldt River Basin) shows that as we reach the end of February, the amount of water estimated to be in the snowpack is approximately two inches less than what we observed last year at this time. A few definitions: first, the water year begins on October 1st and ends on September 30th of the following year. This corresponds with theoretical completion of a hydrologic cycle that spans a single year period, after evaporation and plants have depleted the maximum expected amount of water from the soil and deeper in the soil profile. The water year designation always corresponds with the calendar year in which it ends (for example, we are in water year (WY) 2014, which began on October 1, 2013 and will end on September 30, 2014). Another aspect of this that is important is the concept of snow water equivalent. Snow is not 100% water--it contains air pockets and the crystals themselves don't allow for even packing. This means that 12" of snow is not the equivalent of 12" of water. If we had a column of snow that was, for example, 12 inches deep and we melted it, the amount of water released would not rise to 12" above the measuring surface. As you can see from the graph below, the Upper Humboldt River Basin appears to have more water in the snowpack this year than we saw in WY 2012 at this time and for the remainder of that year.
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| Snow pack water equivalents for water year 2011 through current year. |
Currently nine counties in Nevada have been declared to be in a state of drought emergency (see previous posts and http://1.usa.gov/1fs5Dkx.
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