Late afternoon, going into sunset , May 18, 2013 (100UTC May 19, 2013) … several plumes appeared in central west Mexico — quickly followed by large prominent columns (steam or smoke?) produced near the Texas border.
Location .. somewhere very close to:
29°12’52.46″N , 102° 1’15.06″W
If you look at the area on Google earth, you will quickly come to see
1) It is a desert
2) There are several very old (dormant) volcanoes at this location