An article published by National Geographic on January 19, 2011 highlights the current research results of scientists from YVO partner University of Utah (UU) and the National Central University of Taiwan. The National Geographic piece has led to several subsequent articles about Yellowstone, some of which misrepresent the research, current geological activity, and the potential for future eruptions. Geological activity over the past five years includes widespread ground uplift and two notable earthquake swarms. Though scientifically interesting, such events are common in large caldera systems like Yellowstone, and are not indicative of an imminent eruption. Moreover, the research described ground uplift that stopped about a year ago. For more information, please see our webpage describing the University of Utah research, or the original papers published in Geophysical Research Letters. Our monthly update can be seen above
Yellowstone Volcano Observatory
Como diz o artigo, essas atividades são normais, e esse "inchaço", da matéria do OP, aconteceu há UM ano, e não em 19 de janeiro.