Gary Osoba writes:

A very localized micro-burst in the high desert. There are
updrafts at the outer edges as it propagates, but it's mostly turbulence. While
most micro-bursts are associated with significant rain events and the rapid
cooling of air that forms downdraft columns, in very dry areas (such as this
one) the cool shaft may descend from cloud to ground long after any
precipitation has evaporated.