Drought Report March 19, 2021

March 20, 2021

Drought Update Report

NWS Reno

Issued: 03/19/2021

Schedule: Monthly during periods of extreme drought designation

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Drought conditions persist

Synopsis: Precipitation and snow accumulation in February and the first half of March were well below average for the Sierra, and pretty much closed the door on the odds of recovering snowpack and water supply conditions to near average with only a few weeks remaining in the typical snow accumulation season. Conditions were somewhat better in far northeastern CA and northwestern NV, but still well short of significant drought recovery. Mid-February storms were most beneficial to northern Nevada, but precipitation since February 1st is well below average for SNOTEL stations on the east side of the central Sierra (Figure 1). The past 30 day mountain precipitation was even worse throughout the state, but especially for the Sierra where sites ranged from ~25 to 40% of average (Figure 2). Current snowpack conditions are well below average for the Sierra, and closer to average for the few sites in NW Nevada and the lower Humboldt (Figure 3). Water year precipitation is also well below average in most areas (not pictured). Soil moisture conditions, as measured by SNOTEL sites, are at a record low for the short period of record in the Truckee, Carson, and Walker combined area (Figure 4). Evaporative demand is also above normal for the past 6 months combined, with more neutral conditions over the past 4 weeks (Figure 5). Water year-to-date observed streamflow volumes and April-July streamflow forecasts range from ~10 to 50% of normal (Figure 6). The US Drought Monitor indicated minor improvements in north east Pershing County, and degrading conditions for the east side of the Sierra. Currently the entire NWS Reno service area is classified in severe to extreme drought (Figure 7).

Summary of Impacts: Previously reported impacts include: extreme fire behavior and numerous rapidly spreading late fall fires. Hazardous air quality from smoke during summer and early fall. Major impacts to agriculture and ranching. Reports include: reduced irrigation water, early irrigation shut off, reduced hay crops, reduced forage, hauling water, animal stress, reduced stock weights, and reduced grazing on public lands. Recreational impacts include: Previous campfire ban in both California and Nevada and temporary California National Forest closure due to extreme fire danger. Limited snowpack impacting recreation and water supply. Note: Please report any new or missing drought impacts here.

Drought Mitigation Actions: On March 5th, the USDA declared 14 counties in Nevada and 50 counties in California primary natural disaster areas due to drought. The designation increases access to federal assistance for farm operators. No new actions reported since the last update. Previously reported actions include: Hauling water, moving livestock, selling livestock, supplemental feed, previous campfire restrictions, closing recreational areas, heavy reliance on snowmaking at ski areas. Note: Please report any new or missing drought mitigation actions to the email below.

Local Drought Outlook: The short-term outlook is fairly dry with only weak precipitation events. The 8-14 day outlook from the CPC leans towards warmer and drier conditions late in the month and into early April. Peak snow accumulation typically occurs within the next couple weeks, leaving chances for recovery near zero for the Sierra. Subseasonal ensemble weather models are favoring below normal precipitation to persist into mid-April. The April through June outlook also favors warm and dry conditions (Figure 8). The combination of these products indicate drought conditions are likely to persist and/or increase in magnitude.

Figure 1. SNOTEL since February 1 precipitation as % of average.

Figure 2. SNOTEL 30 day precipitation as % of average.

Figure 3. Current SNOTEL Basin Snow Water Equivalent.

Figure 4. Average SNOTEL soil moisture for the combined Truckee, Carson, and Walker Basins currently at record low. Note the relatively short period of record (2004-2021).