All phenomena
A massive wall of dust and sand driven by thunderstorm downdrafts that can reach over a mile high and span 60+ miles wide
A massive dust wall scrolling across the screen like an unstoppable stage hazard -- no power-up can save you, just run!
The science
Cold air from a thunderstorm downdraft hits the ground and spreads outward as a density current, scooping up loose sand and dust into a towering wall that advances ahead of the storm.
How to spot it
Watch for an advancing brown or tan wall on the horizon ahead of a thunderstorm, often during late afternoon. The wall has a distinct, sharp leading edge and may be preceded by gusty winds.
Where
The Sahara and Sahel regions, the Arabian Peninsula, the US Desert Southwest (especially Phoenix and Tucson), Sudan, and parts of Australia.
Best season
Summer monsoon season when thunderstorms are frequent over desert terrain: June-September in the Northern Hemisphere.
Famous encounter
A massive haboob struck Phoenix, Arizona on July 5, 2011, creating a dust wall over a mile high and 100 miles wide that was visible on weather radar and satellite imagery.
- ▸The name comes from the Arabic word "habb" meaning to blow
- ▸Can reduce visibility to near zero in seconds
- ▸Dust walls can reach altitudes of 5,000+ feet
- ▸Wind speeds at the leading edge often exceed 60 mph