What is the difference between the dust storms of the 1930s and the haboobs we experience in The Valley?

Dust storm of the 1930s
Size: horizontal length of 620 miles or more
Cause: generated by a strong cold front passing

Haboob
Size: horizontal length of about 3 miles to 200 miles
Cause: generated when a thunderstorm collapses because winds move against the path of the storm