A pair of unrelated avalanches near Jackson killed two backcountry skiers Sunday.

Elizabeth “Liza” Benson, 28, and Nick Gillespie, 30, died from trauma in two separate slides, officials reported. The fatalities were the first of the winter and came after fresh snowfall over the weekend broke a prolonged dry spell in Jackson Hole.

Benson was skiing in the Cliff Creek drainage, off Hoback Canyon in Sublette County, in a group of five people. The party, including her boyfriend and a physician, were skiing in the Clause Creek area, commonly reached by snowmobile.

A slide with an 8-inch crown swept her into a tree at about 9,200 feet elevation, according to reports from the Bridger-Teton National Forest Avalanche Center and the Sublette County Sheriff’s Office. The Sublette Sheriff’s Office received a call from the group at about 3:25 p.m.

The initial report was that a skier had been injured. The doctor in the group pronounced Benson dead during the phone call, the sheriff’s department said.

Along with the boyfriend and physician, two women also were in the group, said Ariel Mann, a friend of Benson’s sister, Adrienne.

The Avalanche Center forecasted the danger at the time and elevation of the incident to be moderate. Four inches of snow had fallen in the 24 hours leading up to Sunday morning, but much more fell that day.

Sublette County’s Tip Top Search & Rescue sent a handful of rescuers on skis and snow machines to the site Monday to recover Benson’s body, Sublette sheriff’s spokesman Steve Smith said. There was no word of the mission by press time.

Benson had lived in Jackson Hole on and off since 2000, Adrienne Benson said. She was studying to be a physician assistant through the University of Washington in Seattle and had worked at Teton Orthopaedics as part of her schooling.

Gillespie, a seasonal trail crew worker in Grand Teton National Park, was the second valley resident to be killed Sunday. He was descending the southeast slopes of Survey Peak, near the park’s north boundary, when he got caught in an avalanche around 5 p.m.

Gillespie was skiing in a group of four that had been staying at the Upper Berry Creek patrol cabin since Thursday, park officials said.

The group climbed and skied the 9,277-foot peak that day. Two remained near the base of the mountain while Gillespie and a partner made a second lap, park deputy chief of interpretation Mike Nicklas said.

Gillespie descended first and apparently triggered the avalanche. His partner followed, skiing over the remnants of the avalanche, Nicklas said.

One person from the group activated an avalanche beacon to search for any signals from Gillespie’s own transceiver. After ascending the slide path, the partner was able to find Gillespie’s body at approximately 5:50 p.m., Grand Teton spokeswoman Jackie Skaggs said.

Skaggs said she heard Gillespie’s upper torso was protruding from the snow. Park rangers investigating the incident had not confirmed that detail, she said.

To get into cellphone range, a member of the party skied partway up Forellen Peak. Emergency authorities received the call at around 9 p.m.

“It’s a real wilderness setting with poor to nonexistent radio and cell coverage,” Nicklas said. The peak is at least eight miles from the nearest road.

Four park rangers were helicoptered to the scene at about 11 a.m. Monday. They were not able to return with the body until around 5 p.m. because of heavy fog, Skaggs said.

Gillespie had been a seasonal employee for Grand Teton for the past six years.

Sunday’s storm “will create the potential for backcountry users to trigger soft slabs or sloughs to a foot in depth by the afternoon,” the avalanche center predicted in its Sunday morning forecast. “Slides will be easily triggered as the new snow rests on weak and/or slick surfaces of wind pack, sun crusts or faceted snow.”

Another group was stranded overnight Sunday.

A Search and Rescue team flew into Mosquito Creek on Monday morning to evacuate an overdue ski party. The group, which consisted of four skiers and two dogs, set off from Teton Pass Sunday but became disoriented, Teton County Undersheriff Bob Gilliam said.

Family members called the sheriff’s office at around 9 p.m. after the group didn’t return home.

Search and Rescue skiers began their search Sunday night, but were unable to locate the lost skiers. The group was spotted from a helicopter huddled around a fire they had built. Rescuers were able to touch down near the skiers and fly them out.

— Johanna Love contributed to this article.