Assertion: dust storm | /r/CapableOf | form over semi-arid areas
Facets:
value: during periods of convective instability
type: TEMPORAL
Source sentences:
text: Known as haboobs (Arabic for "violet wind"), dust storms form over semi-arid areas during periods of convective instability, when large masses of air are heated near the ground surface and then rise rapidly to altitudes of more than 10km (6 miles).