MILAN (AP) — A record 13 backcountry skiers, climbers and hikers have died in the Italian mountains over the last week, rescuers said Monday, including 10 in avalanches triggered by an exceptionally unstable snowpack, as Winter Olympic competitions got underway.

Fresh snowfall during recent storms and wind-swept snowcaps on weak internal layers have created especially risky conditions along the entire Alpine crescent bordering France, Switzerland and Austria, Italy’s alpine rescuers said.

‘’Under such conditions, the passage of a single skier, or natural overloading from the weight of snow, can be sufficient to trigger an avalanche,’’ said Federico Catania, Italy’s Alpine Rescue Corps spokesman.

The avalanche deaths occurred on ungroomed slopes, away from well-maintained and monitored Olympic sites in Lombardy on the Swiss border and Cortina d’Ampezzo in Veneto, as well as cross-country skiing in Val di Fiemme in the autonomous province of Trentino.

“There is no danger for people skiing within managed ski resorts, and in particular no risks to the Olympic sites,’’ Catania said. “All of these areas are constantly monitored and are generally safe regardless of Olympic events.’’

With a spate of recent snowstorms, people have been rushing to the mountains during brief windows of good weather, “and as a result the number of accidents, and therefore fatalities, has increased proportionally,’’ Catania said.

Rescuers advise people making backcountry excursions to heed avalanche bulletins and to delay outings until the snowpack has consolidated.

Over the weekend alone, two skiers died in avalanches in Lombardy, three in Trentino and one in neighboring South Tyrol. They included two who died in separate avalanches in the area of the Marmolada glacier.

The deaths also included two hikers on Monte Grappa in Veneto and in the Marche region along the Appenine range, as well as an ice climber in Valle d’Aosta.

The same Alpine Rescue Corps also carried out the helicopter rescue of U.S. downhill skier Lindsey Vonn, after she crashed during competition in Cortina d’Ampezzo on Sunday.