[1] At the time of the collision, the valley was undergoing its sixth year of a serious drought; as a result, its rainy season had not yet begun, creating unusually dusty conditions.
In some parts of the valley, including along I-5, narrow plumes of dust made local visibility conditions even worse than those measured.
[2] Around 2:30 PM local time, the low visibility on the highway caused a series of chain reaction collisions roughly 45 miles (72 km) north of Coalinga.
Several vehicles caught fire, which contributed to the casualties; two bodies were burned so badly that they could not be identified in the aftermath of the crash.
[5] According to the California Highway Patrol, the crash was the deadliest collision caused by a dust storm in state history.