A large dust storm, or haboob, was seen expanding over Roby, Texas, on Wednesday, October 4, as the National Weather Service (NWS) warned of a severe thunderstorm in the area.Video taken by Chad Casey shows the wall of dust looming over the town.The NWS warned of strong, gusty north winds of up to 60 mph as a cold front swept through the region on Wednesday evening.Haboobs occur as a result of thunderstorm outflow winds, according to the NWS. Credit: Chad Casey via Storyful