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Regional Drought Update Date
August 26, 2021
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Drought Status Update

Drought Update for the Intermountain West


DEWS Regions:
Update Status:

NIDIS and its partners will issue future drought status updates as conditions evolve.

Short-term drought improves. Long-term drought continues as winter snowpack will be crucial.

Key Points

  • The Southwest has been experiencing high rainfall totals during the monsoon season.
  • Despite recent improvements to drought conditions, long-term drought remains.
  • Warm and dry conditions are forecast for the Intermountain West this fall.
Current Conditions
U.S. Drought Monitor Conditions: Intermountain West | August 24, 2021

Current U.S. Drought Monitor map for the Intermountain West Drought Early Warning System region with data valid for August 24, 2021. The U.S. Drought Monitor is updated each Thursday to show the location and intensity of drought across the country.

Extreme (D3) to Exceptional (D4) drought persists across much of the Intermountain West.

U.S. Drought Monitor Categories

The color with the hex code #ffff00 identifies:
D0 - Abnormally Dry
The color with the hex code #ffcc99 identifies:
D1 - Moderate Drought
The color with the hex code #f5ad3d identifies:
D2 - Severe Drought
The color with the hex code #ff0000 identifies:
D3 - Extreme Drought
The color with the hex code #660000 identifies:
D4 - Exceptional Drought
Main Stats
17%
of Arizona is in Extreme to Exceptional (D3–D4) Drought
15%
of Colorado is in Extreme to Exceptional (D3–D4) Drought
23%
of New Mexico is in Extreme to Exceptional (D3–D4) Drought
88%
of Utah is in Extreme to Exceptional (D3–D4) Drought
31%
of Wyoming is in Extreme to Exceptional (D3–D4) Drought

Recent and Current Conditions

U.S. Drought Monitor Conditions 

  • Extreme (D3) to Exceptional (D4) drought persists, but has dropped to 35% of the Intermountain West (was 43% one month ago).
  • Extreme (D3) drought conditions have been in place in this region since May 2020.
  • The extent of D4 drought in the Intermountain West reached a peak of 45% area in December 2020, a new record for the region, and is currently at 9%.
  • Moderate (D1) or worse drought has been in the region since August 2009.
  • Over the past four weeks, drought conditions have improved but remain in Arizona, New Mexico, southern Utah, and southwestern Colorado 
    • Despite the small improvement, Severe (D2) to Extreme (D3) drought remains in these places. 
  • Drought conditions have remained or deteriorated in Wyoming, Utah, and northeast Colorado.

U.S. Drought Monitor 1-Month Change Map

U.S. Drought Monitor 4-week change map for Arizona, Colorado, New Mexico, Utah, and Wyoming, from July 27 to August 24. Arizona, southwest Colorado and New Mexico have seen a 1- to 2-category improvement.
4-week U.S. Drought Monitor change map, showing where drought has improved, remained the same, or worsened from July 27 to August 24, 2021. Source: National Drought Mitigation Center.

Long-Term Drought Persists

  • Despite recent improvements, long-term drought persists in the Intermountain West
  • Long-term indicator blends show extreme (D3) and exceptional (D4) drought across western Colorado, Utah, and northern Arizona and New Mexico.

Long-Term Drought Indicator Blend for the Intermountain West

Long-term drought indicator blend from UC Merced and Climate Engine. These data combine PDSI, Z-Index, and 6-month, 1-year, 2-year, and 5-year SPI to estimate the overall long-term drought.  Extreme to exceptional drought persists across the western United States.
Long-term drought indicator blend as of August 13, 2021. These data combine PDSI, Z-Index, and 6-month, 1-year, 2-year, and 5-year SPI to estimate the overall long-term drought. Learn more. Source: UC Merced, Climate Engine.

Major Bureau of Reclamation Reservoir Storage: August 24

Map of the western U.S. with drought categories overlaid with water storage diagrams. In the Intermountain West, Lake Mead, Lake Powel and Elephant Butte Reservoir are all near record low levels.
Reservoir storage, a key indicator of long-term drought, is low to record low across the western U.S. Source: U.S. Bureau of Reclamation.

Southwest Monsoon 2021

  • Arizona measured its second wettest July on record, the wettest since 1919.
  • Tucson Airport is approaching one foot of rainfall for the season and is currently at its third wettest monsoon season on record.

Southwest Monsoon Rainfall vs. Normal

Bar graph showing rainfall totals for monsoon season 2021 at select Arizona locations. The locations and rainfall totals (in inches) are: Tucson Airport, 11.86; Nogales Airport, 10.11; Safford Airport, 4.19; Sierra Vista, 8.52; Oracle, 7.89; Willcox, 5.69; Picacho Peak, 8.9; and Ajo, 3.48.
Accumulated rainfall totals from June 15 to August 25, 2021 for Arizona locations, comparing 2021 Monsoon rainfall to normal conditions. Source: National Weather Service.

Tucson Historical Monsoon Rainfall: 1895–2021

 Accumulated rainfall since 15 June 2021 at Tucson, Arizona compared with all historical years, going back to 1895. This monsoon season is the third wettest on record so far.
Accumulated rainfall for monsoon seasons from 1895–2021 at the Tucson Airport. Source: National Weather Service Tucson Weather Forecast Office.
  • Short-term forecasts show a continuation of monsoon conditions.
  • Track the southwest U.S. Monsoon:
  • Parts of New Mexico, Arizona, and Utah have received over double their normal precipitation for this time of year.

60-Day Precipitation Conditions

Precipitation totals for June 25 to August 23, 2021 for the Western U.S., , representing approximately the monsoon season, which began on June 15.

60-day percent of normal precipitation from June 25 to August 23, 2021. Parts of New Mexico, Arizona, and Utah have received over double their normal precipitation for this time of year.
Top: 60-day precipitation totals from June 25–August 23, 2021. Bottom: 60-day percent of normal precipitation from June 25–August 23, 2021. Source: High Plains Regional Climate Center.

Evaporative Demand Drought Index (EDDI)

4-Week EDDI for August 17, 2021

EDDI values show increased wetness across most of the Intermountain West.

Observed EDDI, Last 4 Weeks

Map of the western US showing the 4-week averaged Evaporative Demand Drought Index (EDDI) as of August 17, 2021.  Areas of average to low EDDI are shown in white and blue and cover most of the southwest for the past 4 weeks.
Observed Evaporative Demand Drought Index (EDDI) for the past 4 weeks, through August 17, 2021. Source: NOAA Physical Sciences Laboratory.

Forecast EDDI: Next 4 Weeks

Map of the western US showing the forecast Evaporative Demand Drought Index (EDDI) for the next 4 weeks. Areas of average to low EDDI are shown in white and blue and cover most of the southwest for the past 4 weeks and most of the Intermountain west for the next 4 weeks.
Forecast EDDI for the next 4 weeks, valid August 17, 2021. Source: University of California Merced.

Forecasts and Seasonal Outlooks

1-Month Outlook for September

A warm and dry September is likely for most of the West, including  Utah, Wyoming, and western Arizona in the Intermountain West.

September 2021 Temperature Outlook 

Month showing the probability of exceeding the median temperature for the month of September 2021. Odds favor above normal temperatures for most of Utah, Wyoming, and western Arizona.
1-month temperature outlook, showing the probability of above-normal, below-normal, or near-normal conditions during August 2021. Source: NOAA Climate Prediction Center.

September 2021 Precipitation Outlook 

Map showing the probability of exceeding the median precipitation for the month of September 2021. Odds favor below normal precipitation for most of Utah, Wyoming, and western Arizona.
1-month precipitation outlook, showing the probability of above-normal, below-normal, or near-normal conditions during August 2021. Source: NOAA Climate Prediction Center.

3-Month Outlook for the Fall (September–November 2021)

A warm and dry fall is likely for the Intermountain West.

September–November 2021 Temperature Outlook 

Map showing the probability of exceeding the median temperature for the months of September, October, and November 2021.  Odds favor above normal temperatures for all of the Intermountain West Region.
3-month temperature outlook, showing the probability of above-normal, below-normal, or near-normal conditions for September to November 2021. Source: NOAA Climate Prediction Center.

September–November 2021 Precipitation Outlook 

Map howing the probability of exceeding the median precipitation for the months of September, October, and November 2021. Odds favor below normal precipitation for the Intermountain West region.
3-month precipitation outlook, showing the probability of above-normal, below-normal, or near-normal conditions for September to November 2021. Source: NOAA Climate Prediction Center.

Seasonal Drought Outlook

Despite short-term drought improvement, the National Weather Service Climate Prediction Center's 3-month drought outlook shows drought continuing at least through November.

3-Month Drought Outlook

A map of the continental United States showing the probability drought conditions persisting, improving, or developing August 19–November 30, 2021. urrent drought conditions over the western U.S. are forecast to persist.
U.S. seasonal drought outlook for August 19 to November 30, 2021, showing the likelihood that drought will remain, improve, worsen, or develop. Source: NOAA Climate Prediction Center.

Climate Patterns: La Niña Watch

  • NOAA’s El Niño–Southern Oscillation (ENSO) alert system status is currently at La Niña Watch—meaning the pacific is currently ENSO-neutral, but conditions are favorable for the redevelopment of La Niña within the next six months. 
  • La Niña usually correlates with below-normal winter precipitation in the Southwest U.S.
  • For more information, please check out the NOAA ENSO blog.

Probability of El Niño, La Niña, or Neutral Conditions

A bar graph showing the probability of El Niño, La Niña, or neutral conditions from July 2021 to May 2022. ENSO-neutral conditions are the most likely outcome throughout summer, followed by possible La Niña conditions in autumn and winter.
ENSO forecasts from the International Research Institute, showing the probability of El Niño, La Niña, or neutral conditions from July 2021 to May 2022. Source: International Research Institute

State-Based Conditions and Impacts

Arizona

  • Drought conditions across most counties improved, with counties in the southeastern portion of the state improving by 2–3 categories of drought.
  • Total system storage in the Salt and Verde river basin slightly improved as a result of runoff into reservoirs.
  • There has been improvement in range and pasture lands.
  • Lake Mead is operating under Tier 1 conditions.

Arizona Streamflow Conditions

Current daily streamflow across AZ shows that the majority of streamflow in the state is above normal on August 26, 2021
Current daily streamflow across AZ shows that the majority of streamflow in the state is above normal on August 26, 2021. Source: U.S. Geological Survey.

Colorado

  • August brought a shift in weather patterns to Colorado. In recent months, precipitation has been above normal east of the Continental Divide and below normal west of the Continental Divide. This pattern was reversed in August. The eastern plains have been mostly hotter and drier than normal, and the west slopes have been mostly wetter than normal. There are a few large exceptions on the eastern plains. For instance, the Holyoke CoAgMET weather station received over 8 inches of precipitation in a 24 hour period.
  • As we near the end of August, the growing season begins to wind down. The dry weather in July and August impacted winter wheat stands in eastern Colorado, with some crops achieving abnormally low weights. According to GrassCast, however, rangeland production was mostly above average, especially in southeast Colorado.
  • Despite helpful monsoonal moisture, long-term drought and low reservoir supplies remain major concerns for western Colorado. Peak season streamflows were generally below the 10th percentile. Recent rains will not be enough to reverse deficits in water year cumulative flows. Blue Mesa Reservoir is forecast to retain record low storage through the cold season.

Colorado 4-Month Streamflow Percentiles

Colorado observed streamflow percentiles over 4 months from April 1 to July 31, 2021.
April 1–July 31 streamflow percentiles in Colorado. Source: USDA Natural Resources Conservation Service.

New Mexico

  • Most of New Mexico has had average to above-average precipitation this summer, but precipitation has not been consistent across the state. Albuquerque, Santa Fe, Gallup, and Farmington have had a near-average monsoon this year.
  • Ample winter snowpack will be needed to fill low reservoirs: Elephant Butte, 5% full; Caballo, 9% full; and Sumner, 22% full

New Mexico Precipitation Conditions

Most of New Mexico has had above average rainfall, this summer. But that has not been consistent across the state. North eastern and north central NM have been slightly drier than normal.
Percent of average precipitation for New Mexico, June 15–August 25, 2021. Source: Climate Science Applications Program, University of Arizona Cooperative Extension.

Utah

  • After the 4th wettest July on record for the state, the last month of monsoonal rainfall has delivered 200%–400+% of normal precipitation to the majority of the state, with localized pockets exceeding 800% of normal.
  • The active monsoon has eased Utah’s meteorological drought and improved the short-term agricultural drought conditions as near-surface soil moisture has jumped to record levels for this time of year, although groundwater levels have not seen an appreciable increase.
  • Hydrologic drought remains a significant problem as medium and long-range streamflow forecasts will not benefit from the recent monsoon rainfall, and regional reservoirs continue to see decreasing levels (Lake Powell is at 31% of storage, down from 34% last month).
  • Vegetative-based drought indices show noticeable improvements to the southern half of the state, but the northern half of the state continues to feature unhealthy growing conditions—this time of year should normally have limited vegetative growing conditions.
  • The Great Salt Lake continues to dip farther into record low elevations and should continue to do so for the foreseeable future, as the lake levels will have a long-term lag in response to the current drought conditions.
  • Concern remains that the seasonal outlook for dry fall and winter conditions will further exacerbate the long-term drought and erase any positive hydrologic contribution the monsoon has had on soil moisture, which needs to be retained ahead of the snowpack growth to avoid another failed spring runoff.

Utah Soil Moisture Conditions

Time series of depth averaged soil moisture for the state of Utah showing the record dry spring conditions preceding the active monsoon season pushing soil moisture conditions to record wet levels for this time of year.
Depth averaged soil moisture for the state of Utah showing the record dry spring conditions preceding the active monsoon season pushing soil moisture conditions to record wet levels for this time of year. Source: USDA Natural Resources Conservation Service.

Vegetation Drought Response Index (VegDRI)

egDRI index for Utah showing the impact of the active monsoon season to southern Utah’s vegetation conditions while northern Utah remains further into drought stress conditions.
VegDRI index for Utah showing the impact of the active monsoon season to southern Utah’s vegetation conditions while northern Utah remains further into drought stress conditions. Valid August 22, 2021. Source: National Drought Mitigation Center, U.S. Geological Survey, High Plains Regional Climate Center.

Utah Reservoir Conditions 

Reservoir fill percentage for Utah as of August 23, 2021. Several reservoirs are in the 0%–20% (low) range, with the majority between 0% to 60%.
Reservoir fill percentage for Utah as of August 23, 2021, which shows the extent of hydrologic drought across the state. Source: Utah Department of Natural Resources.

Wyoming

  • Average maximum temperatures over the last 30 days have been below average by up to 3 °F in much of western Wyoming while the east has been around up to 3 °F above the average.  Average mean temperatures have generally been up to 3F above average with some cooler spots in the far west.
  • Precipitation over the last 30 days 
    • Above average in the western half of the state with totals being 200% to 300% above the 1991-2020 average.  Parts of east central Wyoming are just below that.  
    • Laramie County in the southeast has been the farthest below average where large parts were under 50% of the average.
  • Soil moisture has improved in the last month in many parts of the state, most notably in the northwest where precipitation has brought about a quarter of the state to above the 20th percentile.  The northeast and parts of the southwest remain at less than the 2nd percentile.
  • Drought conditions are similar to where they were last month with a few changes having been made over the last 30 days.  There have been slight expansions in north central and southeast Wyoming while parts of Sweetwater, Uinta, and Lincoln Counties in the southwest have gone from D3 to D2 conditions.  Currently less than a quarter of a percent of the state is not in any of the D0-D4 categories and almost 95% of Wyoming is in D1 or worse. This is the largest percentage of Wyoming that has been in D1-D4 since the 5th of February 2013.

30-Day Percent of Normal Precipitation

Wyoming 30-day precipitation for July 26–August 24, 2021 as a percent of the 1991-2020 average.
Wyoming 30-day precipitation for July 26–August 24, 2021 as a percent of the 1991–2020 average. Source: Wyoming State Climate office, with data from PRISM Climate Group.

For More Information

More local information is available from the following resources:

In Case You Missed It

Upcoming Events

Prepared By

Joel Lisonbee
NOAA/National Integrated Drought Information System (NIDIS)

Erin Saffell
Arizona State Climatologist/Arizona State University

Erin Boyle
Service Hydrologist, National Weather Service, Tucson, Arizona

Peter Goble
Colorado Climate Center/Colorado State University

Jon Meyer
Utah Climate Center/Utah State University

Tony Bergantino
Water Resources Data System – Wyoming State Climate Office

Greg Heavener
Warning Coordination Meteorologist, National Weather Service, Pueblo, Colorado

Special Thanks

This drought status update is issued in partnership between the National Oceanic and Atmospheric Administration (NOAA), and the offices of the state climatologist for Arizona, Colorado, New Mexico, Utah and Wyoming. The purpose of the update is to communicate a potential area of concern for drought expansion and/or development within the Intermountain West based on recent conditions and the upcoming forecast. NIDIS and its partners will issue future drought status updates as conditions evolve.