Thunder and lightning hit U.S. Grand Prix practice

The start of second practice at the U.S. Grand Prix was delayed indefinitely on Friday as rain lashed down amid thunder and lightning. "It's a shame for the people in the grandstands." Friday's first session was also rain-affected, although drivers did get on track with Germany's Nico Rosberg fastest for Mercedes. The Briton needs to beat Vettel by nine points and Rosberg by two.