For those having lived on the United States’ west coast from the era of about 2011-2017, especially those in California, drought was persistent, dangerous, and unprecedented in length and severity. As little came in the way of precipitation, especially the snow that fills the Sierra Nevadas and provides water for millions of Californians, reservoirs sank to record lows in capacity. Little water was available for anything more than necessity. Advisories were sent out to citizens advising and urging water saving strategies such as only watering lawns three times a week and only at night, replacing lawns with drought-tolerant landscaping, not serving water at restaurants unless upon request, installing water-efficient taps, showerheads, and more, and even cutting showers to no more than two minutes in duration. For California agriculture, the drought was arduous with smaller yields, and many farmers were forced to dig wells and tap into groundwater. Though, with all these results and effects, one may wonder: What was the precursor, the cause of the drought? The answer lies in something that climate scientist Dr. Daniel Swain coined: “The Ridiculously Resilient Ridge.”
The Ridiculously Resilient Ridge, or the RRR for short, is an atmospheric blocking phenomena appropriately named for its tenacity and unrelenting presence within the atmosphere off of California’s coast. A ridge is an area within the atmosphere in which there is unusually high pressure. In the case of the RRR, that pressure was ridiculously high. High enough to last for several years and cause the horrific drought conditions that Californians know all too well. But, how exactly does an area of high pressure bring about drought?
The key to answering this question is that areas of high pressure may act as a sort of physical wall to other systems that would otherwise try to move them and push them about. The stronger the wall is, or the higher the pressure is, the harder it is going to be to knock down that wall. As the ridge sat off the California coast, the jet stream and low pressure systems were forced up and above it, that of which brings necessary precipitation, leaving California with little to nothing in the way of water. Instead, California was met with nearly five years of dry, hot weather as the RRR prevailed and refused to subside. As each year went by with little to no precipitation, the effects of drought only compounded.
Come winter 2017, California had officially exited the drought after the RRR had finally weakened. With its downfall, atmospheric rivers of great strength were permitted to flow into California, These atmospheric rivers then brought some of the rainiest seasons on record after just having exited the most intense drought on record. Although California currently enjoys drought free years as a result of these intense atmospheric rivers, the RRR could very well rear its head again as global temperatures continue to warm. In California’s future, there certainly lies drought and lack of water. It simply is a matter of when conditions are right to birth Dr. Daniel Swain’s infamous Ridiculously Resilient Ridge.
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© 2019 Weather Forecaster Alexis Clouser