Meeting Summary
Due to the relatively dry winter and localized summer rainfall, the end of the water year (October 31, 2016) short-term drought is worse than a year ago, in the southwestern quarter of the state, but better than a year ago, in the northwestern quarter. In addition, there were no long-term improvements in drought conditions within any of the watersheds in Arizona, and three watersheds that were not in drought became abnormally dry.
Reservoirs for the Salt and Verde Watersheds continue to hover around 50% of capacity and the additional groundwater pumped during the drought has not been recharged. Additionally, moisture deficit is not currently increasing, but it has not recovered from the drought, so long-term conditions are still poor. Due to such conditions, every county, besides Coconino, had a United States Department of Agriculture disaster designation due to the impacts of drought this water year.
The Colorado River Basin System is experiencing a 17-year drought, which is the driest period in historical record dating back to 1906. In June 2016, Lake Mead levels dropped to 1,071 feet, which is below the first shortage trigger, set at 1,075 feet. Due to water conservation efforts by multiple entities, water levels increased in October, 2016, to 1,076 feet, right above the shortage trigger, and Reclamation’s projection of a Lower Colorado River Basin shortage in 2017 decreased from 37% to 0%. However, the chance of a shortage declaration in 2018 is still very likely and hovers at 48%. As of November 1, 2016, the entire System’s reservoir capacity was at 50%.
As a response to the long-term drought conditions on the Colorado River Basin and the looming shortages for the Lower Basin states, representatives of the three states and Reclamation developed a Drought Contingency Proposal (DCP) in December 2015 to conserve water levels in lake mead. Under the DCP, Arizona and Nevada would begin reducing water deliveries earlier than previously agreed. Reclamation would also agree to conserve water in the system. Additionally, California would agree for the first time to reduce its deliveries when Lake Mead elevations are below 1050 feet.
2016 wildfire season in was very like what was expected based on a ten-year average; Arizona experienced higher number of fires (2,197) than the 10-year average (2,144), however current acres burned (303,057) are lower than the 10-year average (317,781). Looking ahead to 2017, the state still experiences similar wildfires hazards: continuation of drought, fine fuel conditions, highly variable seasonal temperatures and low precipitation. These conditions suggest a similar wildfire season for 2017. However, the threat of catastrophic wildfire remains and Arizonans are urged to exercise extreme caution.
The most likely weather outcome for this winter is weak La Niña conditions developing during the late fall and early winter (around a 70% chance) and becoming neutral in late winter. Odds are shifted towards a warmer and drier than normal winter based on a combination of La Niña, model output, and trends over the past 10-15 years. The Climate Prediction Center’s outlook for July-September 2017 shows somewhat better chances that the average temperature during these three months will be above normal statewide, but there is no precipitation signal.
Recommendation
Based on this information, the ICG unanimously recommended that both drought declarations be kept in place:
- Drought Emergency Declaration (PCA 99006) has been in effect since June 1999 and maintains the state’s ability to provide emergency response if needed. It also enables farmers and ranchers to obtain funding assistance through the Farm Service Agency if they experience production losses due to drought.
- The Drought Declaration for the State of Arizona (Executive Order 2007-10) was issued in May 2007 to raise awareness of Arizona’s continuing long-term drought and encourage conservation.
Presentations
Meeting Summary
This winter’s El-Niño did not perform as anticipated and provided below average precipitation. The long-term drought status looks the same as it did one year ago, and as of May, most of the state is in moderate drought, while the Verde River Watershed is in severe drought. Drought conditions will likely exacerbate during the next few months until the monsoon season starts.
Early winter precipitation greened up grasses for a short period before warm temperatures dried them out again, potentially leading to a very busy fire season. Hotter than average late-winter temperatures prematurely melted snowpack in many basins, exposing vegetation, which increase the risk for fires. Fuel loads are heavy and recent warm and windy conditions have already led to numerous wildfires. As temperatures are warming up, wildfire activity starts showing in the Central Highlands and Colorado Plateau, until the monsoon onset.
The Colorado River Basin is experiencing a 16-year drought, which is the driest in historical record dating back to 1906. The average April through July inflow into Lake Powell for the period 2000 - 2015 has been only 5.54 million acre-feet (MAF). This is about 1.6 MAF less than the 1981 - 2010 period average inflow of 7.16 MAF. As of May 1st, the Colorado River reservoirs system storage was at 48% of total system capacity, similarly to last year’s capacity at this time. Lake Powell and Mead storage was at 45% and 37% capacity, respectively.
This is the sixth year that the Salt and Verde watersheds experienced below median winter runoff. The Salt and Verde reservoir levels have remained approximately the same as this time last year, at about 56% of normal, due to reduced demand and the conjunctive use of groundwater to meet demand. If projections for very low inflow hold, this consecutive six-year period will be the driest six-year period on record (1913-2016).
El-Niño conditions will decay through the summer eventually becoming neutral and providing little to no influence on Arizona’s monsoon season. The predominance of models suggests a 60%-70% chance that La-Niña conditions will develop by late fall and winter. There is low confidence on strength, but odds are slightly higher for a warmer and drier winter (40%) as oppose to the odds for a cooler and wetter winter (27%).
Recommendation
Based on this information, the ICG unanimously recommended that both drought declarations be kept in place:
- Drought Emergency Declaration (PCA 99006) has been in effect since June 1999 and maintains the state’s ability to provide emergency response if needed. It also enables famers and ranchers to obtain funding assistance through the Farm Service Agency if they experience production losses due to drought.
- The Drought Declaration for the State of Arizona (Executive Order 2007-10) was issued in May 2007 to raise awareness of Arizona’s continuing long-term drought and encourage conservation.
Presentations
- Drought Status Update & Activities of the Monitoring Technical Committee
- Summer 2016 Weather Outlook & Winter 2016-2017 Preview
- Colorado River Basin Water Supply Update
- Update on the Governor's Arizona Water Initiative
- 2016 Wildfire Outlook & Update on the Four Forests Initiative
Spring 2016 Drought ICG Recommendation Letter to the Governor