A majority of the 2,300 residents of Casselton, North Dakota, fled on Monday night after a massive fire following an oil train explosion. Mushroom-cloud smoke and flames rose up after a grain train derailed and crashed into a crude oil train in Casselton, located about 25 miles west of Fargo. “It was black smoke and then there were probably four explosions in the next hour and a half,” said Casselton resident Eva Fercho. Both trains had more than 100 cars each, and the cars were still burning as darkness fell. Following the explosion, the Cass County Sheriff’s Office called for “precautionary” evacuations until the health hazards are known. A monitoring crew spent the night evaluating air quality and other possible hazards, despite the temperatures of 15 degrees and a wind-chill at 32 below.