FLAGSTAFF, Ariz.—Authorities are searching for two people who were on a river rafting trip through the Grand Canyon and went missing after a flash flood, a park spokeswoman said Thursday. Authorities got a call Wednesday evening from someone on a commercial trip on the Colorado River saying people had been injured and asking for emergency help, said park spokesman Joelle Baird. Park crews launched a search from the ground, water and air for at least two people who are missing, she said. No other information on the identities of the missing people was immediately released. The flood hit the people on the trip as they were camped at the mouth of a side canyon almost 40 miles (64 kilometers) from where the rafts launched at Lees Ferry near the Arizona-Utah state line. Baird did not immediately know the extent of injuries for other passengers that were traveling on two rafts. …