Spectacular displays of lightning flashed in the volcanic clouds during the weekend.
A massive dust cloud rolled into the valley from the southeast Tuesday night, blanketing the sky with gray and brown dust and reducing visibility.
A dust storm warning was in effect until 9:15 p.m. Gusting winds at speeds up to 50 mph pushed the dust and debris cloud along.
The dust storm is approximately 50 miles wide in some spots and 1 mile high, and it stretched from the Estrella Mountains in the west to the Superstition Mountains in the east.
It swept over Sun Lakes, Queen Creek, Gilbert, Chandler, East Mesa, Ahwatukee, swallowing up entire neighborhoods. Not long afterwards it hit central and downtown Phoenix, moving north and west.
Because of the hazardous driving conditions, drivers are reminded to pull over to the side of the freeway and turn off their headlights.
Phoenix Fire's Scott Walker says they received 720 emergency phone calls between 5 p.m. and 7 p.m. Tuesday, and firefighters responded to over 320 incidents in 26 cities during the same time period.
The cloud also shut down operations at Sky Harbor -- even causing the fire alarm to go off. Flights were delayed and the terminal was completely covered in dust. Check flight status » Things started returning to normal about 9 p.m.
For more stories from KSAZ in Phoenix, Arizona go to myfoxphoenix.com.