Following a single IND (improvised nuclear device) detonation in the US, the National Atmospheric Release Advisory Center (NARAC) would, within minutes to at most hours, after the detonation have a reliable prediction of the fallout plume size and direction. When armed with this prediction they would then begin attempting to corroborate this with readings from radiation survey meter equipment that would fly over close to the ground in the affected area by means of helicopter or drone (UAV) aircraft on material intelligence gathering missions, which would also follow within tens of minutes to at most hours after the detonation.