Beginning about an hour after sunrise, going forward until 10-11am PDT, a long duration "cloud/steam" event occurred above the long dormant Sunset Volcanic Crater complex located in Central Arizona which is part of the "San Francisco Volcanic field".
This steaming / cloud event above Sunset Crater(s) directly follows a rare earthquake which struck Northwest Arizona this morning, striking at ANOTHER dormant volcanic complex, called the Uinkaret Volcanic field.
3 days ago (May 31st) a different rare earthquake struck at the Markagunt Volcanic Plateau in South Utah, as well as a swarm of earthquakes which struck due West in California at the dormant "Volcano Peak.
Also, the swarm of large earthquakes off the coast of Oregon are occurring at the Cleft Volcanic Ridge (undersea volcanoes), and finally the active eruption occurring off the coast 100 miles NORTH of the large earthquakes location, along the Axial Seamount off the coast of Oregon.
A LOT of volcanic earthquake activity, but this is the first real steam plume event that is undeniable even to the skeptics who might have (in the past) tried to dismiss this as a "forest fire" or "thunderstorm" or "convection" or "regular clouds".....
In this case, its steaming / clouds coming directly from Sunset Craters on a clear day with NO other cloud cover nearby, no storms, no military explosions, no forest fires, and gone in a few hours.
All this leaves is a volcanic event of some kind as our only culprit for producing clouds on a clear day in the deserts of Arizona .. directly above the volcanoes in question.