Mountainous landscapes, because of their deep valleys and tall peaks, support a wide variety of microclimates. These microclimates, in turn, provide homes for a diverse assortment of plants and animals. A study by Daniel Cayan and his colleagues, published by the Parks Stewardship Forum, investigated the phenomenon of cold air pools in Devils Postpile National Monument, just north of Mammoth Mountain. Location of Devils Postpile National Monument (red dot on map). From Figure 1 of Cayan et al. Google Earth Image of the study area. The center of the image is a deep valley that supports pools of cold air. This region is in the headwaters of the San Joaquin River. Cold air pools are localized areas of cold air that develop along valley bottoms, typically at night. Because these are persistent features, they can serve as refuges for plants and animals as they slowly adapt to a warming climate. Given the potential importance of cold air pools to ecosystems, Cayan and his colleagues analyze