ROME (AP) — Rescue teams were searching Sunday for two skiers who were caught in an avalanche near Mont Blanc on Italy’s northern border with France, local authorities said.

Two surviving off-piste skiers sounded the alarm shortly after the 1 p.m. avalanche on Val Veny, above Courmayeur, but low-lying clouds prevented helicopters from reaching the scene, Courmayeur Mayor Roberto Rota told Sky TG24.

Rescuers were getting to the site by snowmobile, but Rota said the chances of finding the skiers alive was slim given the amount of time that had passed.

Rota suggested the four skiers were amateurs who hadn’t gone up with a guide or proper avalanche safety equipment, though he added that avalanche airbags would have only been useful if rescuers were nearby and had gotten to the scene within the first 15-20 minutes.

“Unfortunately, it’s 99% that those involved won’t make it,” he said.

The avalanche risk Sunday for the area was a level-three “considerable” danger on a scale of five risk levels — low, moderate, considerable, high and very high — used by the European Avalanche Warning Services, Rota said.