Many western US storms, such as this one in southern Colorado, have extremely high bases and low tops. Don't let the weak appearance fool you! Some of the "dry storms" can produce dangerous microbursts and copious amounts of fire-setting lightning.
Photograph by: Moller
Recent research has shown that microbursts, both "dry" ones such as this (actually some very light rain may fall with a dry microburst) and "wet" ones frequently are the cause of wind shear induced aircraft accidents.