Drought Interagency Coordinating Group

The Interagency Coordinating Group (ICG) is an advisory body to the governor on Arizona drought issues. Comprised of state, federal and non-governmental organizations, this group meets twice a year to evaluate drought conditions and consider recommendations to the governor. Arizona has had a Drought Emergency Declaration (PCA 99006) in effect since June 1999 and a Drought Declaration (Executive Order 2007-10) has been in effect since May 2007.


Interagency Coordinating Group Members

Interagency Coordinating Group Fact Sheet

IGC Meeting Spring 2024
 Meeting Summary

Drought Status Update & Monitoring Technical Committee Activities

The 2024 Water Year (WY; October 1-September 30) started as the fifth hottest October to December on record, which impacts long-term drought in Arizona. Statewide, precipitation for October 2023 through April 2024, has been slightly above average. Southern Arizona counties received a late starting monsoon but did get near average precipitation from September 2023 through December 2023 however, the rest of the state remained dry. Average statewide precipitation from October 2023 to December 2023 was 1.58 inches. January 2024 to April 2024 brought in a fair amount of precipitation totaling 5.28 inches which was Arizona’s 23rd wettest January to April on record however, temperatures remained warm across the state. Maricopa and Cochise counties BOTH had their wettest April in 20 years in 2024.
Statewide temperatures for the WY2024 to date (October 2023 to April 2024) have been above average. October 2023 to April 2024 was the 13th warmest October to April on record. Apache, Cochise, Coconino, Mohave, and Santa Cruz counties all had their top 10% warmest October to April on record. Precipitation for the WY2024 so far, has been slightly above average totaling 6.86 inches. January 2024 to April 2024 was the 23rd wettest on record for the state. Snow water equivalent data for the Salt, Verde and Little Colorado Basins indicate around average snowpack volumes for the snow year. Extreme (D3) short-term drought was removed from the state during this time. However, long-term drought persists throughout Arizona.

2024 Weather Outlook

La Nina will continue to develop and strengthen through the remainder of 2024 which could impact monsoon moisture return into Arizona this summer. However, La Nine development by itself does not always result in consistent monsoon outcomes. Probability outlooks illustrate a greater than 80% chance that La Nina will be fully developed by the fall and winter of 2024/2025. The temperature outlook for July, August, and September 2024 favors a warmer than average summer based on modeling and trends over the past 30-50 years. Arizona has not seen any below normal summers in recent years because we are in a warming trend with the region warming 0.6 degrees Fahrenheit per decade, which has been a consistent trend for the last 40 years and there is no sign of this warming trend slowing. Monsoon rainfall seasons after El Nino and entering a La Nina phase show inconsistent historical precipitation trends and are highly variable with some monsoon seasons with below average precipitation and some with above average precipitation totals. The precipitation outlook for July, August and September 2024 show slightly better odds of below average precipitation totals however there is still a 25% chance that above average precipitation could occur. Randomness of thunderstorms will likely provide large spatial variations in rainfall coverage. Outlook for January, February and March 2025 show a slight shift in odds favoring warmer and drier weather for winter 2024-2025. The best-case scenario is that enough areas in the state and particularly headwater locations, receive above average rainfall such that soil moisture is not overly depleted heading into WY2024-2025.

Colorado River Water Supply Update

As of May 12, 2024, Lake Powell was at 3,561.94 feet (ft) with 7.925 million acre-feet (MAF) in storage or 34% full, compared to 25% full at this time last year. Lake Mead was at 1,070.06 ft and 9.204 MAF or 35% full, compared to 30% full at this time last year. Total System Storage in the Colorado River Basin was 24.54 million acre-feet (MAF) or 42% full. Total System Storage at this time last year was 20.92 MAF or 36% full. As of May 14, 2024, Lake Powell snow water equivalent (SWE) was 9.12 inches. Snowpack peaked in early April at 111% of median peak. The most probable Lake Powell unregulated inflow for Water Year (WY) 2024 (as of May 3) was 7.79 MAF (81% of normal, the 1991-2020 average is 9.60 MAF), the minimum probable is 6.80 MAF (71% of normal), and the maximum probable is 9.35 MAF (97% of normal). The projected end of Calendar Year (CY) 2024 elevation for Lake Powell is 3,572.92 ft under the most probable scenario and 3,561.90 ft under the probable minimum scenario. Releases from Lake Powell are projected to be about 7.48 MAF in WY2024 under the probable minimum and most probable scenarios and 9.00 MAF in WY2025. The projected end of CY2025 elevation for Lake Powell is 3,582.12 ft under the most probable scenario and 3,550.06 ft under the probable minimum scenario. The projected end of CY2024 elevation for Lake Mead is 1,061.41 ft under the most probable scenario and 1,059.79 ft under the probable minimum scenario. The projected end of CY2025 elevation for Lake Mead is 1,059.62 ft under the most probable scenario and 1,047.75 ft under the probable minimum scenario.

Salt River & Verde River Watersheds Water Supply Update

The cumulative watershed precipitation for the start of Water Year 2024 (WY2024) (October 1-May 1) was 10.80 inches or 108% of normal. It was drier than normal, and streamflow was below median. As of April 1,2024, overall snowpack across the Salt and Verde watershed was at 317% of median due to above normal precipitation in February and March. The deepest early April snowpack on the Salt Watershed since 2010 was recorded this year. C.C. Craig Watershed and Reservoir filled to 100% capacity and spilled about 4,200 AF between April 5 to April 24 following the late March and early April snowpack surge. The 2024 Winter Runoff Season on the Salt River, Tonto Creek, and Verde River recorded below median runoff for the months of January, February, and March. Runoff totals caught back up to median in April and May. Streamflow for the Winter Runoff Season is expected to be near median at 470,000 AF (105% of normal) for January to May 31, 2024. Total SRP storage is in good condition at 92% of total capacity (2,115,092 AF) as of May 13, 2024. Reservoir storage increased from 81% to 92% between January 1 to May 13. SRP total groundwater use for 2024 is expected to be 75,000 AF. SRP is considering three water system improvement projects across the Salt and Verde Watersheds to reduce spill releases from storage reservoirs during high precipitation years.

2024 Wildfire Outlook

In 2023, 1,887 fires burned nearly 190,000 acres of State, Federal, and Tribal Lands. Of those fires, 71% were human caused, these tend to be more prevalent in spring, coinciding with windy and dry conditions. In 2023, 26% of Arizona’s fires were along roadsides. As of May 21, 2024, there have been 371 fires (14,627 acres burned), compared to 339 fires and 6,725 acres burned at this time last year. There is a potential for higher-than-normal fire activity in 2024 in the areas south of the Mogollon Rim, across the Tonto National Forest and Sonoran Desert landscape, within the Central part of the state and down into Cochise County because fuel loading in those areas is more than double of what is it in other parts of the state.
On May 17, 2024, Governor Katie Hobbs signed HB 2751 allowing the Arizona Department of Forestry and Fire Management to enter into the Great Plains Interstate Compact for state-to-state sharing of resources for fire season in order to maintain adequate resources. With the compact, states can coordinate between each other, without the involvement of the federal government.

Impacts of Drought on Hydropower – Irrigation and Electrical Districts Association of Arizona

There has been a nearly 40% reduction in total power generated from the CRSP Facilities and Glen Canyon, Hoover, Davis, and Parker Dams since 2000. Power generation from the Hoover Dam has reduced by over 48% since 2000. Reduction in average energy production has direct economic impacts. The average energy cost at Palo Verde hub has increased 2-3x in the last five years. Cost mitigation strategies are being considered by IEDA such as the diversification of their power portfolio in the Box Canyon Solar Project which is a 300-megawatt solar power solution located in Pinal County, Arizona. Federal bills and legislation are also being pursued such as the Help Hoover Dam Act (H.R. 7776/S. 4016) and the Federal Land Recreation Enhancement Act Exemption.

Impacts of Drought on Hydropower – Western Area Power Administration

The Western Area Power Administration (WAPA) is a power marketing administration and wholesale electricity supplier under the United States Department of Energy. WAPA has over 17,000 miles of transmission lines and 700 customers throughout 15 states who, in turn, serve 40 million Americans. WAPA’s Desert Southwest region, located in Phoenix supplies power from Hoover Dam, Glen Canyon Dam, and Parker and Davis Dams. Parker-Davis Project FY2024 energy supply data and forecasts show that WAPA will need to purchase about 268 GWh (gigawatt hour) of replacement power to supply customers (20% of the power that is sold). The Parker-Davis Project will generate 1,163 GWh of power in FY2024. Average replacement power costs range from $38 to $148 however, some months have experienced peak hour actual costs of $1,200 per MWh (megawatt hour); this is higher than sales price for customers ($25 MWh). In 2024, WAPA projects spending $24M on replacement power costs, which equates to 129% of the cost of operating and maintaining the dams. This is an additional cost that is passed on to the customers. On a system-wide scale, the estimated cost of drought impacts (2025-2030) for Hoover Dam is $732 million, and $67 million for Parker-Davis Project, when broken down, the highest costs are attributed to replacement power. The estimates do not consider regulatory reductions or the Colorado River Supplemental Impact Statement.

Impacts of Drought on the Navajo Nation

The Navajo Nation Department of Water Resources (NNDWR) uses 85 actives precipitation cans spread across Navajo Nation, including the Chuska Mountains, to monitor precipitation monthly. According to 6-month Standard Precipitation Index (SPI) data (from November 1, 2023-May 1, 2024), the Chinle, Fort Defiance, Shiprock and Western Navajo agencies, have had similar trends with wet conditions increasing from January to late March 2024. However, precipitation has been variable, with trends towards drier conditions in May. Snowpack volumes at recorded sites for this winter measured about half of what was recorded last winter. Since November 2022, there have been short-term drought condition improvements in Navajo Nation. Currently, most of the area has Abnormally dry (D0) conditions or is in the ‘no drought’ category.

Impacts of Drought on the Gila River Indian Community

The Gila River Indian Community (GRIC/Community) has a 311,800 acre-feet per year (AFY) entitlement to Central Arizona Project (CAP) water, making it the largest CAP water user in Arizona. The Community is a major participant in water conservation efforts in the Lower Colorado River Basin (CRB), voluntarily contributing substantial portions of its CAP water in recent years to benefit Lake Mead. The Community’s CAP water is comprised of Non-Indian Agricultural (NIA) Priority CAP water (120,600 AFY) and higher Indian Priority CAP water (191,200 AF per year). Below a Tier 1 Shortage the Community’s NIA Priority CAP water is eliminated, leaving less water to voluntarily contribute. More concerning to the Community is that much of its NIA Priority CAP water will likely be permanently or semi-permanently cut given future additional curtailments of Colorado River water allocations. Through 2023, the Community has contributed 725,000 AF to Lake Mead. By the end of this year, the Community will have contributed approximately 895,000 AF to Lake Mead (400,000 AF for compensated system conservation, 320,000 AF for ICS and 175,000 AF of DCP cuts). Since 2019, the Community has had to curtail its off-Reservation storage activities as it has shifted more water to Lake Mead. While increasing agricultural development on its lands continues to be a long-term goal, the Community has committed to replacing much of its NIA Priority CAP water to meet its water needs for agricultural developments. The Community is also investing in on-Reservation water efficiency projects. On May 21, 2024, the Community announced its plan to install solar panels over its canals as part of a pilot project to generate renewable energy and conserve water.


While there have been drought condition improvements, there are impacts that have accumulated through time. Arizona remains in a short- and long-term drought with most of the state experiencing some level of drought condition from abnormally dry to extreme drought. The Drought Interagency Coordinating Group unanimously recommends that both drought declarations (PCA 99006) and (Executive Order 2007-10) be kept in place. The meeting summary and presentations are posted on the ADWR ICG webpage.



Spring 2024 ICG Meeting Recording

ICG Meeting Fall 2024