Signs of Drought:
One of the most obvious signs in lack of rainfall. The National Drought Mitigation Center (http://droughtmonitor.unl.edu/Home.aspx) reports two indices related to drought--percent of normal precipitation (PNP) and the standard precipitation index (SPI). PNP (Percent of normal precipitation) is an easy to calculate index, provided you have a definition of "normal" that is commonly accepted. For example, normal could be the long term average amount of precipitation received at a location during a year, or a shorter time period like a month. It
Friday, May 23, 2014
Friday, May 16, 2014
Status of the drought, May 15
Severe Drought Conditions Persist
The National Weather Service's Elko office provided a summary of drought conditions in the Great Basin, with an emphasis on Nevada, especially eastern Nevada (http://bit.ly/1oYbsat). The drought outlook for the state remains stable, which is to say that in parts of four counties (Churchill, Lyon, Humboldt and Eureka) exceptional drought conditions persist. The Nevada Water Supply Outlook for May, 2014 (found through http://1.usa.gov/1hS4kHS) reports that the snowpack in the Upper Humboldt River Basin is well above the median amount observed in past years (159%) and precipitation received as of May 16th was very close to the average (92%) In contrast, the snowpack in the lower Humboldt River Basin was at 9% of the median amount and precipitation received as of May 16th was approximately 77% for the water year.
In the Truckee River Basin, the latest forecast from the Natural Resources Conservation Service (May 16, 2014) indicates a less than even chance (30%) that flow for May through July at the Farad gaging station will be at 35% of the 30 year average, an even chance (50%) chance that flow will be at 22%, and a much higher chance (70%) that flow will be at about 9% of what we expect.
None of this is good news, especially because our typical precipitation patterns are dominated by snow accumulations in the mountains during the winter months and our typical water supply forecasts assume that snowmelt will be gradual. However, other forecasts for the region (for example, the May, June, July temperature outlook provided by the National Weather Service (http://1.usa.gov/S0TeKB) indicates a good chance (about 67%) that the next three months will be warmer than what we expect based on the median temperature calculated for these months.
At the Farad gage, on May 16, flow (817 cubic feet per second) was approximately 46% of the average flow for this day (1770 cubic feet per second), based on 105 years of record. This is more than 2.3 times the minimum flow observed on this day (347 cubic feet per second, observed in 1934.
All of this means that drought, especially in the northwestern portion of the state, will be in the news for the summer. Drought-related events, especially fires, will be prominent stories as the summer progresses.
The National Weather Service's Elko office provided a summary of drought conditions in the Great Basin, with an emphasis on Nevada, especially eastern Nevada (http://bit.ly/1oYbsat). The drought outlook for the state remains stable, which is to say that in parts of four counties (Churchill, Lyon, Humboldt and Eureka) exceptional drought conditions persist. The Nevada Water Supply Outlook for May, 2014 (found through http://1.usa.gov/1hS4kHS) reports that the snowpack in the Upper Humboldt River Basin is well above the median amount observed in past years (159%) and precipitation received as of May 16th was very close to the average (92%) In contrast, the snowpack in the lower Humboldt River Basin was at 9% of the median amount and precipitation received as of May 16th was approximately 77% for the water year.
In the Truckee River Basin, the latest forecast from the Natural Resources Conservation Service (May 16, 2014) indicates a less than even chance (30%) that flow for May through July at the Farad gaging station will be at 35% of the 30 year average, an even chance (50%) chance that flow will be at 22%, and a much higher chance (70%) that flow will be at about 9% of what we expect.
None of this is good news, especially because our typical precipitation patterns are dominated by snow accumulations in the mountains during the winter months and our typical water supply forecasts assume that snowmelt will be gradual. However, other forecasts for the region (for example, the May, June, July temperature outlook provided by the National Weather Service (http://1.usa.gov/S0TeKB) indicates a good chance (about 67%) that the next three months will be warmer than what we expect based on the median temperature calculated for these months.
At the Farad gage, on May 16, flow (817 cubic feet per second) was approximately 46% of the average flow for this day (1770 cubic feet per second), based on 105 years of record. This is more than 2.3 times the minimum flow observed on this day (347 cubic feet per second, observed in 1934.
All of this means that drought, especially in the northwestern portion of the state, will be in the news for the summer. Drought-related events, especially fires, will be prominent stories as the summer progresses.
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