(CNN) -- At least four tornadoes struck Arizona Wednesday, injuring seven people, derailing a train and damaging more than 100 homes, the National Weather Service said.
Forecasters initially had said there were two twisters, but raised that estimate Wednesday night, saying four tornadoes were confirmed. Hail of up to 2 inches in diameter was also reported in the region, around Flagstaff, Arizona.
One tornado caused "about a mile of destruction," said Sheriff Bill Pribil of Coconino County. It damaged at least 30 mobile homes, blew the windows out of about 100 homes and caused a train derailment, he said.
None of the seven injuries in the county were believed to be serious, Pribil said.
Two of the tornadoes touched down in the town of Bellemont early Wednesday. Fifty to 100 power poles were snapped, a hillside of trees was leveled and numerous cars and trucks were overturned on Interstate 40, the National Weather Service said. An RV dealership was also damaged.
Lena Kent, spokeswoman for Burlington Northern Santa Fe Railway, said 28 train cars were derailed and that the track itself suffered minor damages.
"It was stopped (in Bellemont) because of the tornado warning, but unfortunately, the tornado came through and actually hit the train, derailing 28 cars," she said.
No one was injured in the derailment, she said. The company hoped to get the rail lines reopened by midnight.
Another tornado touched down in Blue Ridge, where U.S. Forest Service employees reported a nearly 15-mile-long path of trees felled, the weather service said.
The fourth struck near Munds Park just after noon (9 a.m. ET) and moved toward east Flagstaff. The weather service had no reports of damage, but said the twister was observed.
The storm system was caused by a Pacific low pressure system across southern California, combined with moisture moving north from Mexico, forecasters said.
CNN Meteorologist Sean Morris contributed to this report.