A motorcyclist was killed in a northwestern Minnesota crash over the weekend, extending a rash of fatalities among riders in the state this summer, authorities said Monday.

Killed Saturday was Eric Erickson, 47, who lived near Erskine, according to the Polk County Sheriff’s Office.

Erickson was northbound on Polk County Road 4 south of Lengby when his motorcycle left the right side of the road and rolled repeatedly, the Sheriff’s Office said. He was not wearing a helmet, the Sheriff’s Office added.

His death was at least the seventh in the first 13 days of July among riders in Minnesota and the 28th so far this year. Ten riders were killed in June.

The 55 deaths in all of 2012 were the most since 2008.

Other statistics for 2013 from the Department of Public Safety: Of the 24 motorcycle ­fatalities for which details on helmets were available, 17 ­riders were not wearing helmets; about half of the fatal motorcycle crashes this year involved another ­vehicle.

The State Patrol on Monday also identified the motorcyclist who died last week after colliding with an SUV in Scott County. Denise M. Sames, 49, of Glencoe, Minn., died about five hours after the crash Thursday morning at County Road 9 and 190th Street in Jordan, the patrol said.

At about 9 a.m., a Lincoln Navigator was turning left from northbound County Road 9 onto 190th, according to the patrol. The oncoming motorcycle clipped the right front side of the SUV. Sames, who was not wearing a helmet, was airlifted to Hennepin County Medical Center and died there in the afternoon.

The SUV driver, Henry A. Mendez, 35, of Shakopee, was not hurt.