HELENA - Students at Sheridan Elementary School were under their desks Tuesday morning, in some cases before teachers realized an earthquake was shaking the area, the school secretary said.
"It was a hard jar, and really loud," said secretary Jenny Burke. "It was like somebody just shook the heck out of us for two seconds."
The magnitude 4.6 quake, reported at 9:46 a.m., was centered about nine miles northeast of Sheridan in the Tobacco Root Mountains. It was felt in the Helena, Butte, Dillon and Hamilton areas and as far away as Idaho, according to the U.S. Geological Survey Web site.
"Some facades of some buildings on Main Street were knocked off," said Frank Ford, Madison County's former emergency management director. "A few of them, bricks were still hanging there."
One Sheridan family was evacuated from a downtown apartment that was damaged until it can be proven safe, and engineers were brought in to examine the high school, Ford said.
"They're inspecting the school to see whether the cracks noted in the walls were old cracks or new cracks as a result of this," Ford said.
The elementary school, a separate building, was not damaged, and NorthWestern Energy did not find any natural gas leaks, Burke said.
The children responded like they were taught during earthquake drills, Burke said.
One teacher "said the students were under the table before he said a word," and before he really realized what was going on, she said.
Madison County Commissioner Jim Hart was on the third floor of the courthouse when the earthquake hit.
"We all just kind of held onto the table for a second or two, and then went, 'We need to get out of here,' " Hart said.
Ford said the Ruby River Dam appeared to be fine and, during a flight over irrigation dams in the Tobacco Root Mountains, "we didn't see any evidence of damage."
Ford said more in-depth engineering inspections will be done on dams and buildings in the area.