One of the warmest and driest fall through spring periods on record resulted in a rapid onset of drought conditions across northern and central Arizona. Starting in early July, above normal monsoon rainfall has resulted in a slight one category improvement in drought conditions for much of Yavapai and Coconino counties as well as the Mogollon Rim and White Mountains. In the latest US Drought Monitor issued August 2, Exceptional Drought (D4) persists over the northern half of Apache and Navajo, extreme northwest Gila and extreme southeast Yavapai counties. This includes the communities of Winslow, Ganado, and Chinle. The remainder of northern Arizona is in Severe (D2) to Extreme Drought (D3). Ninety-seven percent of the state is in Severe Drought or worse, an abrupt change to the beginning of the water year (Oct. 1) when none of the state was in these drought categories.
Summary of Impacts...
Rangeland conditions have improved due to recent monsoon rainfall area wide. Water hauling for both livestock and wildlife that was necessary earlier in the spring and summer has ended in many areas.
The lack of spring snowmelt caused well below normal streamflow, limiting filling of reservoirs and recharge of aquifers. Snowpack over the higher elevations was sporadic and much less than normal. This caused limited winter recreation opportunities.
The lack of precipitation over the fall and winter combined with a warm and dry spring and early summer created elevated wildland fire danger. Dry forests and rangeland led to area National Forests putting progressively more severe fire restrictions including targeted full closures in place much earlier than normal. With the arrival of higher humidity and rainfall with the monsoon season, the fire restrictions and forest closures have been lifted.
The current water year (since Oct. 1) has been among the warmest and driest on record for many areas. Seasonal snowfall amounts were very low, less than 30 percent of normal for most areas. Water year to date precipitation rankings have improved significantly for some areas due to heavy monsoon rainfall.
Precipitation Summary for Water Year to Date (Oct 1, 2017 - August 7, 2018)
Precip | Normal | Percent | Rank of Normal Driest
Flagstaff 10.33" 17.13" 60% 13th
Winslow 2.33" 5.17" 45% 7th
Prescott 11.23" 13.60" 83% 35th
Payson 7.32" 17.00" 43% 4th
Show Low 9.03" 12.47" 72% 9th
Chinle 2.00" 7.59" 26% 1st
Page 2.83" 6.54" 43% 7th
The precipitation outlook for August through October (encompassing the end of the southwest monsoon) from the NWS Climate Prediction Center calls for a slight tilt in the odds toward above normal rainfall for all of northern Arizona. The odds of a wetter than normal season are highest over the northern third of the state. This has the potential to produce at least minor additional improvements in drought status. Looking farther out, there is also a slight tilt in the odds toward a wetter than normal November through February due to the possibility of developing El Nino.
Temperature outlooks indicate that warmer than normal conditions are favored through the fall.
Hydrologic Summary and Outlook...
A lack of mountain snowpack led to very low seasonal spring runoff. Reservoir and groundwater recharge was minimal and storage in smaller reservoirs fell through early summer. Monsoon season has the potential to at least partially fill smaller stock ponds and tanks but is not likely to affect larger reservoir levels. The exception has been in the Prescott area where very heavy rains in July filled some of the smaller reservoirs.
Next Issuance Date...
Drought Information Statements from this office are normally issued on the third Thursday of each month in which extreme or exceptional (D3-D4) drought conditions exist in any part of northern Arizona. The next statement will be issued on or around August 16, 2018.
Additional information is available at the following locations:
NWS Forecast Office Flagstaff: weather.gov/Flagstaff National Integrated Drought Information System: drought.gov US Drought Monitor: droughtmonitor.unl.edu NWS Climate Prediction Center: www.cpc.ncep.noaa.gov Arizona State Climate Office: azclimate.asu.edu Arizona Dept of Water Resources: new.azwater.gov/drought Western Region Climate Center: wrcc.dri.edu US Geological Survey: water.usgs.gov Acknowledgments... Information included in this statement was compiled from a multitude of federal, state, and local agencies. Questions or comments... National Weather Service Flagstaff AZ PO Box 16057 Bellemont, AZ 86015 (928) 556-9161 firstname.lastname@example.org