
#UPDATE DRAGONBOX D4 2019 UPDATE#
For more detailed information, check out the Nevada Drought Update from the Nevada State Climatologist and the California Department of Water Resources’ Water Year 2021 brochure.


Since October 2019, the start of the current drought, in California and Nevada evaporative demand has dominated the drought over 21% of the region, and is about equal to the precipitation deficit in 39% of the region.

The current drought is a combination of a precipitation deficit (0.5 to 1 water year's worth of precipitation) and a surplus of evaporative demand (the atmospheric conditions leading to the drying of the landscape).Both states have had the driest 18 months on record. Through September, NOAA's National Centers for Environmental Information ranks the last 12 and 24 months as the driest in California since 1977 and in Nevada since 1960. The drought over the last two years has been caused by the lack of large storms, particularly atmospheric rivers.Drought has deepened throughout the region during Water Year 2021, with central California experiencing the greatest intensification of drought.The region continues to be 100% in drought, compared to ~80% this time last year and ~3% at the start of Water Year 2020 (October 1, 2019). Drought Monitor, drought in California-Nevada hasn’t changed in the last 4 weeks. Drought impacts (e.g., pasture conditions, ecosystem health, water supply, recreation, fire potential) have intensified and expanded given back-to-back dry years.Historically, La Niña is associated with dry to normal conditions in the southern part of California and Nevada. La Niña has developed and is expected to continue into the winter.Approximately 2.5 million acres have burned this year in California as of mid-October-a vast majority of which occurred in forested portions of northern California.Lake Tahoe recently dropped below the rim limiting outflow. During Water Year 2021, the combined storage in 28 Western Sierra reservoirs declined from 9.91 million acre-feet to 6.44 million acre-feet. Reservoirs throughout California and Nevada remain low.

Since the beginning of the current drought in Water Year 2020, evaporative demand is greater or nearly equal to the precipitation deficit for 60% of the region.
