70. Which is a common first indicator of an approaching thunderstorm? A.Too hot B.Heavy wind C.A buildup of dark clouds D.Lightning
Option C Solution: They usually appear as swift-moving black clouds, often approaching from the northwest southwest, south or west at speeds of 25-35 knots. You can determine the distance of an approaching thunderstorm by counting the number of seconds between the lightning flash and the thunder clap, and dividing by five.
