A recent paper on the historic 22-year drought in the Southwest U.S., published in Nature Climate Change by Williams and colleagues, received a great deal of attention in the media. Even though it is not focused on the Sierra Nevada, it used data from the Sierra Nevada and also has important ramifications for the range; therefore, I thought it was appropriate to discuss it here. In addition, this blog provides the opportunity to present interesting and important details that may have been left out in the press accounts. The yellow box on this map outlines the study area. This map also shows the vapor pressure deficit (VPD) anomaly, a measure of how 'thirsty' the air has been during the past twenty years relative to previous years. This anomalously high vapor pressure deficit is thought to be responsible for the outbreak of large fires in the region. One of the many strengths of this paper is that it focuses on soil moisture, rather than temperature or precipitation. Soil mois