An (ash cloud) may drift from a volcano.Logical formLearned from5 sentences. A cloud of ash may affect flights.Logical formLearned from5 sentences. An (ash cloud) may shift.Logical formLearned from5 sentences. (Air traffic chiefs) may warn of a cloud of volcanic ash.Logical formLearned from5 sentences. Revenue may be linked to an (ash cloud).Logical formLearned from5 sentences. A threat can be from an (ash cloud).Logical formLearned from5 sentences. An (ash cloud) may begin.Logical formLearned from5 sentences. A cloud of ash may keep some (world leaders).Logical formLearned from5 sentences. Layers may pertain-to an (ash cloud).Logical formLearned from5 sentences. An (ash cloud) may be created by a volcanic eruption.Logical formLearned from5 sentences. An (ash cloud) may pertain-to a continent.Logical formLearned from5 sentences. An (ash cloud) may cause (travel chaos).Logical formLearned from5 sentences. Winds may blow an (ash cloud).Logical formLearned from5 sentences. A cloud of volcanic ash may move.Logical formLearned from5 sentences. Dangers may be posed by an (ash cloud).Logical formLearned from5 sentences.