An earthquake north of Boise rattled the Treasure Valley on Monday morning.

The magnitude 4.9 quake was measured about 6 miles north of Smiths Ferry — roughly 60 miles from Boise — at 10:25 a.m., according to the United States Geological Survey (USGS). Its effects were felt in various parts of the Treasure Valley, including Boise and Meridian, according to firsthand accounts reported to the Idaho Press.

“It felt like the building was swaying back and forth,” said Allie Whittet, who was working at her desk in the J.R. Simplot headquarters in downtown Boise when the quake hit.

Jessica Turner, a geophysicist with the USGS, said that reports out of Boise and Nampa felt the earthquake at an intensity of 2 or 3 — defined by the USGS as “weak” shaking. That means some individuals on the upper floors of buildings and those who were at rest — working at their computer while sitting on their couch or at a table, for instance — may have felt some shaking, Turner said.

Whittet was on the fourth floor of the nine-story Simplot building on Monday, and said that initially, she thought the swaying was due to the wind and rain that swept through the area.

She said the commotion only lasted a few seconds, but that was enough to make her and people around her realize they had been in an earthquake.

“At first I didn’t really register what was going on because I had never been so high up during an earthquake before,” Whittet said. “It’s pretty unsettling to feel a tall building that you’re in shaking like that. I have felt tremors like this before, but definitely not in a tall building.”

Turner said reports out of Cascade had the earthquake at an intensity of 5 — “moderate” shaking — while the Ketchum/Hailey area and McCall had reports of 2 and 3.

Casey Clark, a housekeeper at the Cascade Lake Inn, said she was working on an apartment attached to the hotel’s laundry room when she felt the earthquake hit.

“I felt that the TVs were going to come off of the wall,” she said. “I was pretty scared for a minute. At first I thought it was the washing machine going whack.”

Monday’s tremor was the largest measured in Idaho since the magnitude 6.5 quake on March 31, 2020, near Stanley, that was felt hundreds of miles away.

There have been many smaller earthquakes since then, but none have approached the intensity of the 2020 Stanley earthquake — the second-largest recorded in Idaho history.

Clark said she felt the 2020 earthquake when she lived in Ontario, Oregon, and that it was mild compared to Monday when she was much closer to the epicenter.

“It was nothing like what I went through today,” she said.

Turner said that the two earthquakes are probably not directly related because their respective locations are too far apart.

With that said, she added, they are in the same mountainous area.

“So just broadly, it’s probably the same geology that’s going on,” she said.

Turner said that Monday’s earthquake was caused by a strike-slip fault, which is when one side of the fault line moves forward while the other moves backward.

Turner said a magnitude 2.7 aftershock hit Smiths Ferry about 20 minutes after the initial earthquake.

The Valley County Sheriff’s Office said on Facebook that it hadn’t received any reports of injury or damage as of Monday morning.

The Idaho Transportation Department said Monday afternoon that crews are assessing bridges and roads in the area, and that “while there are currently no indications of damage, there has been some small rockfall on the roadway,” the agency said in a news release.