The FIA has decided to abandon second practice for the United States Grand Prix due to the poor weather conditions.
The arrival of a lightning storm just after lunchtime on Friday forced the start of the session to be delayed indefinitely, because marshals were unable to work for fear of being hit by lightning.
With rain not easing off, the FIA was unable to restart the session and a decision was taken just before 3pm to abandon it completely.
The reason was because the medical helicopter could not take off for another two hours.
The cancellation of action on Friday could just be the start of an interrupted weekend of activities at Austin, with further bad weather predicted.
The arrival of a weather front means that Saturday's weather could be even worse, meaning that qualifying may have to be delayed or even shifted until Sunday, when conditions are expected to improve.
The last time qualifying took place on Sunday was at the 2013 Australian Grand Prix, when qualifying was postponed because of heavy rain.
In 2004 and 2010, qualifying for the Japanese Grand Prix was also scrapped on Saturday because of a typhoon and qualifying took place on Sunday morning.