Drought Conditions and Impacts in the Western United States – Part II by Meeta Pannu, Todd Jarvis, Abhishek Singh, Azita Assadi
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he winter of 2021/2022 has been a testament to the hydrologic variability that is characteristic of much of the western United States, which was in the midst of historical and extreme drought conditions headed into the winter of 2021. Over half the region was under “extreme” or “exceptional” drought conditions, with more than 90% under some designated class of drought from moderate to exceptional, as shown in Figure 11. The worst conditions were in Montana, Idaho, Oregon, California, Nevada, and Utah. Heavy precipitation, especially along the West Coast, in October and December 2021 and January 2022 brought some much-needed relief to several of these states, easing the drought conditions to moderate to severe drought in California and most of Washington and Utah as seen in Figure 1. The severity of drought also lessened in Montana, Oregon, and Nevada. Above average snowpacks in the Cascades, Sierras, and Rockies built up through December and January. However, after a promising start to the
season, the rest of Winter was disappointing in terms of rainfall and snowpack. The first two months of 2022 were among the driest on record in several places across the West (e.g., San Francisco’s 2-month total of 0.65 inch eclipsed the record low of 0.72 inch established in January-February 1852) and the early season snowpack effectively flatlined through January and February. At the time of the writing of this article, below-average snowpack was common across the Sierra Nevada, the northern Great Basin (extending into parts of southern and eastern Oregon), and parts of eastern Wyoming and large sections of the Southwest. As such, the “drought watch” across the West is on-going, with over 70% of the West still characterized by severe to exceptional drought conditions. Studies (Williams et al., 2022) indicate that the West is in the midst of the worst protracted “mega drought” in the last 1200 years (2000 – 2021 was the driest 22year period since 800 AD). The drought’s impacts on groundwater will be even longer lasting. Reliance on groundwater only increased
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Year 2021 had recordbreaking droughts in much of eastern Washington despite the promising spring snowpack...
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