The 2011–2017 California drought persisted from December 2011 to March 2017 and consisted of the driest period in California's recorded history, late 2011 through 2014. The drought wiped out 102 million trees from 2011 to 2016, 62 million of those during 2016 alone. The cause of the drought was attributed to a ridge of high pressure in the Pacific Sea — the "Ridiculously Resilient Ridge" — which often barred powerful winter storms from reaching the state. By February 2017, the state's drought percentage returned to lower levels seen before the start of the drought. This change was due to an exceedingly wet pattern caused by atmospheric river-enhanced Pacific storms, which caused severe flooding. In mid-March 2019, California was declared drought-free except for a small pocket of "abnormally dry" conditions in Southern California. This declaration followed a series of powerful Pacific storms during the first few months of the year, which coincided with the U.S. experiencing drought conditions in the fewest parts of the country since 2000. History 2013 In 2013, the total rainfall was less than 34% of what was expected. Many regions of the state accumulated less rainfall in 2013 than any other year on record. As a result of this, many fish species were threatened. Streams and rivers were so low that fish couldn't get to their spawning grounds, and survival rates of any eggs that were laid were expected to be low. Lack of rainfall had caused the mouths of rivers to be blocked off by sand bars which further prevented fish from reaching their spawning grounds. Stafford Lehr, Chief of Fisheries within the California Department of Fish and Wildlife said that 95% of winter run salmon didn’t survive in 2013. 2014 According to the NOAA Drought Task Force report of 2014, the drought was not part of a long-term change in precipitation and was a symptom of the natural variability, although the record-high temperature that accompanied the recent drought may have been amplified due to the enhanced greenhouse effect; human-induced global warming. This was confirmed by a 2015 scientific study which estimated that global warming "accounted for 8–27% of the observed drought anomaly in 2012–2014... Although natural variability dominates, anthropogenic warming has substantially increased the overall likelihood of extreme California droughts." By February 1, 2014, Felicia Marcus, the chairwoman of the State Water Resources Control Board, claimed the 2014 drought "is the most serious drought we've