A Dusty Atmospheric River Brings Floods to the Middle East

Torrential rainfall and rapid snowmelt in April 2017 caused deadly floods in northwestern Iran. An atmospheric river (AR), propagating across the Middle East and North Africa, was found responsible for this extreme event. The snowmelt was triggered by precipitation and warm advection associated with the AR. Total satellite-based rainfall for April 2017 was moderately below normal, suggesting that a heavy flood can happen during dry years. The AR was fed by moisture from the Mediterranean and Red Seas. Despite its adverse societal consequences, this event was beneficial to the recovery of the desiccating Lake Urmia. The impacts of this AR were not limited to flooding; it also facilitated dust transport to the region. This distinct characteristic of the ARs in the Middle East is attributed to major mineral dust sources located along their pathways. This event was reasonably predicted at 7-day lead time, crucially important for successful early warning systems.

Automated summary

Deadly floods in northwestern Iran in April 2017 were caused by torrential rainfall and rapid snowmelt, with an atmospheric river (AR) found responsible. The AR, propagating across the Middle East and North Africa, brought precipitation and warm advection triggering the snowmelt, beneficially impacting Lake Urmia while facilitating dust transport in the region. Furthermore, this event was successfully predicted 7 days in advance, showcasing the crucial importance of early warning systems.