Megadrought Cave Study (IMAGE) Vanderbilt University Caption Caves in the megadrought study: White Moon Cave (WMC), Lake Shasta Caverns (LSC), Moaning Cave (MC), McLean's Cave (ML), Oregon Caves (OCNM). "A" shows the time range of the records from each cave. "B" shows the location of the caves. The color-coding on the map shows the correlation between winter rainfall and a measure of the strength of El Niño called the Southern Oscillation Index. It is the work of Erika Wise, University of North Carolina, Chapel Hill. Comparing records from the blue, white and red areas may allow the researchers to identify changes in the relationship between winter rainfall and El Niño along the west coast over the past 33,000 years. Credit Jessica Oster, Vanderbilt University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.