UNDATED (AP) -- A Racine County couple and a pair of college students from Minnesota are among seven people killed in Wisconsin snowmobile accidents so far in 2009. That pushes the season's fatality toll to 13, or more than half the 25 deaths all of last winter.

A memorial service is being planned Saturday for Nathan and Jennifer Kender, both 26, of Caledonia. They died along with an Illinois man when their snowmobiles crashed on a trail in the Vilas County town of Arbor Vitae last Saturday around 10 a.m.

The Kenders' snowmobile collided with the one ridden by 39-year-old Scott Sumoski of South Elgin, Illinois. All three died at the scene.

In Douglas County, two University of Wisconsin-Stout students died in a crash last Thursday night. Officials say the two were on a snowmobile that was going across a lake when it hit the shoreline, went airborne and hit a dock that had been pulled onto the shore.

Twenty-year-old Marty Platek from Inver Grove Heights, Minnesota, and 21-year-old Caitlin Higgins from Little Canada, Minnesota, were killed instantly.

Higgins' funeral is scheduled tomorrow at St. Anthony Park United Church of Christ in St. Paul. Platek's funeral is scheduled Wednesday at The Church of St. Patrick in Inver Grove Heights.

In Monroe County, 38-year-old Christopher Hanifl of St. Charles, Illinois, was killed early Saturday when his snowmobile left a trail and hit a tree in the town of Little Falls.

In Price County, 65-year-old Danny Kolnik of Phillips was killed Saturday afternoon when his snowmobile collided with another at the crest of a hill in the town of Elk.