Drought Status Update for the Pacific Northwest

Current Conditions for the Pacific Northwest

• High pressure over the region caused temperatures to far exceed normal, increasing evaporative demand. Coupled with below-normal summer precipitation, these conditions intensified drought and dryness across much of the region, including Idaho and Montana where Extreme and Exceptional drought developed and expanded (Figure 1, Figure 5).
• Over the last 30 days, precipitation was below normal (bottom 33% of historical conditions) across nearly all of the region, with parts of eastern Oregon reporting their driest conditions on record for this time period (Figure 2).
• Over the last 30 days, temperatures were much above normal (top 10% of historical conditions) across nearly all of the region. Large parts of Oregon, Idaho, and western Montana experienced record warm temperatures (Figure 3).  
• Streamflows across Washington, Oregon, Idaho, and western Montana continue to be much below normal as a result of much-above-normal temperatures, much-below-normal precipitation, and below-normal winter snowpack (Figure 4). 

Figure 1: 6-Week U.S. Drought Monitor Change Map (Since June 11, 2024)

Key Takeaway: Drought intensified across much of the Pacific Northwest, including much of Oregon, central Washington, and south-central Idaho, during June and July.

Figure 2: 30-Day Precipitation Percentiles (June 23–July 22, 2024) 

Key Takeaway: Over the past 30 days, precipitation totals across large parts of the Pacific Northwest were below normal (in the bottom third of historical conditions). Precipitation percentiles were lowest in southeastern Washington, central Oregon, and central Idaho where some values were in the lowest 10% to record driest.

Figure 3: 30-Day Temperature Percentiles (June 23–July 22, 2024) 

Key Takeaway: Over the past 30 days, temperatures across nearly all of the Pacific Northwest were above much normal (top 10%). Large parts of Oregon, Idaho, and northwestern Montana experienced record warmest temperatures.

Figure 4: 28-Day Average Streamflow (July 24, 2024)

Key Takeaway: Across Washington, central and eastern Oregon, and northern Idaho, U.S. Geological Survey streamflows were below normal (below the 24th percentile) due to below-normal precipitation, above-average temperatures, and the effects of below-normal winter snowpack. In addition, stream gauges monitored by the Oregon Water Resources Department (OWRD) show much-below-normal streamflow conditions, most notably in northeast and central Oregon, according to the agency’s July 15, 2024 Bi-Weekly Drought Update.

Figure 5: 4-Week Evaporative Demand Drought Index (EDDI) for July 24, 2024

Key Takeaway: Much-above-normal temperatures across the region caused significant evaporative demand, a measure of the water drawn from the land surface into the atmosphere through evaporation and transpiration from plants. The significant evaporative demand across the landscape resulted in extremely dry land surfaces and reduced soil moisture, particularly in Oregon.

Pacific Northwest Drought Impacts

• Due to the effects of multi-year drought, poor water supply conditions, and below-average precipitation, a drought disaster declaration was declared for Jefferson County, Oregon. 
• Some pro-ratable irrigators across the Yakima Basin are receiving 50% of their full allotments as a result of prorationing of water in the basin. Irrigators in the basin are already experiencing major drought impacts with increased crop stress and the need to fallow some crops.
• An aggressive start to the Oregon wildfire season has resulted in several megafires burning across the state. As of July 24, 2024, more than 898,000 acres are preliminarily reported to have burned thus far, far above the recent 10-year average. Four of those wildfires are over 100,000 acres each: the Falls, Cow Valley, Durkee, and Lone Rock fires. The Cow Valley fire and Durkee fire have merged to form the largest wildfire in the U.S. as of July 25, 2024. 
• The Yakima Reservoir in central Washington has reached its fifth lowest storage level since 1971. The U.S. Bureau of Reclamation expects very low reservoir storage by season’s end across the state, further compounding significant concerns for low streamflow impacts on aquatic species. 
• Flows in western Montana have been at record lows across multiple basins, and as a result stream temperatures have risen to levels requiring river closures to protect trout in the state. 
• Air quality has deteriorated across large parts of the region due to smoke from large active wildfires. 
• April–September water supply forecasts are near record lows in many places (based on 75 years of historical data, 1949–2023).
  • Olympic Basin: The Dungeness, Elwha, and Skokomish rivers are forecasted to be at the third, second, and second lowest flows on record, respectively. 
  • Skagit Basin: Multiple sites on the Skagit River are forecasted to have their 3rd lowest flows.
  • Yakima Basin: The Yakima and Cle Elum rivers are forecasted to have their 8th and 4th driest flows, respectively.  
  • Columbia Basin: Multiple sites are forecasted to have their 4th lowest flows on record.
  • Okanogan Basin: The Okanogan River is forecasted to have its 4th lowest flows on record. 

Report your local drought impacts through a Condition Monitoring Observer Report:

Report Impacts

Figure 6: 0–100 cm Soil Moisture Conditions (July 24, 2024)

Key Takeaway: The warm and dry summer across the region resulted in large areas with near-surface (0–100 cm) soil moisture much drier than normal, in the bottom 30th percentile. Soil moisture across much of southeastern Washington and in western Oregon is well below normal, in the 0–5th percentile relative to historical conditions (1981–2013). Soil moisture in northern Washington and central and eastern Oregon is above normal, in the 70th–100th percentile.  

Figure 7: Major U.S. Bureau of Reclamation Storage Reservoirs in the Bear Creek and Little Butte Creek Basins

Key Takeaway: Much-above-normal temperatures and much-below-average precipitation across the Bear Creek and Little Butte Creek Basins in Oregon resulted in water levels below the capacity of some reservoirs. Water levels in four of five reservoirs were near or well below 50% of capacity.  

Figure 8: Fire Impacts in Oregon and Washington

Key Takeaway: Below-normal precipitation, above-average temperatures, and high evaporative demand contributed to drying vegetation that burned in the Cow Valley Fire, which merged with the larger Durkee Fire. The combined fire was reported at 268,492 acres without containment as of July 25, 2024.

Outlooks and Potential Impacts

Outlooks & Forecasts for Summer 2024

• The Climate Prediction Center’s outlooks for August indicate above-normal temperatures and below-normal precipitation are likely to continue across the region (Figure 9). 
• The U.S. Seasonal Drought Outlook (Figure 10) predicts drought is likely to persist and become more severe across Washington, Idaho, and Oregon from July 18–October 31, 2024, except in western Washington and Oregon and southern Idaho. Given these long-term predictions, drought is expected to adversely affect water supply, human health, and agricultural production further throughout the summer. 
• The risk of wildfire is still a large concern this summer, as the National Fire Preparedness Level is currently at level 5. The National Significant Wildland Fire Potential Outlook, released on July 1, 2024, indicates that fire potential will remain above normal across most of Oregon, Idaho, and western Washington (Figure 11). 

Figure 9: 1-Month Precipitation and Temperature Outlooks for August 2024 

Key Takeaway: The Climate Prediction Center projects temperatures are likely to be above normal and precipitation below normal in much of the Pacific Northwest during August 2024. 

Figure 10: U.S. Seasonal (3-Month) Drought Outlook

Key Takeaway: The NOAA Climate Prediction Center’s U.S. Seasonal Drought Outlook (valid July 18–October 31, 2024) indicates drought will persist in regions east of the Cascade Range in Washington, the Idaho panhandle, and south-central Oregon. Drought expansion is likely across nearly all of the region, except western Washington and Oregon and parts of southern Idaho. 

Resources

• U.S. Department of Agriculture Disaster Assistance 
• State of Washington Water Resources Drought Response Grants
• InciWeb: An interagency all fire risk incident information management system 
• AirNow U.S. Fire and Smoke Map 
• U.S. Drought Monitor tribal land maps and statistics (select "Tribal Areas" for Area type, then select a tribal reservation under Area)
• USDA Northwest Climate Hub
• Bureau of Indian Affairs Branch of Tribal Climate Resilience
• Register for the next Pacific Northwest Drought Early Warning System Webinar on Monday, August 26 at 11 a.m. PDT.

Prepared By

Jason Gerlich
Cooperative Institute for Research in Environmental Sciences (CIRES), NOAA's National Integrated Drought Information System

Karin Bumbaco

Office of the Washington State Climatologist, University of Washington

Caroline Mellor

Washington State Department of Ecology 

Holly Prendeville

USDA Northwest Climate Hub

Erica Fleishman

Oregon Climate Change Research Institute, Oregon State University

Cameron Greenwood

Oregon Water Resources Department

Larry O’Neill

Oregon Climate Service, Oregon State University