Weather makes it difficult to find three American and Canadian climbers missing on New Zealand’s highest peak.

WELLINGTON, New Zealand – New Zealand authorities have ‘serious concerns’ about three climbers from the USA and Canada who have gone missing after a planned climb to the country’s highest peak, Aoraki, as efforts to find them were stalled for a third day by bad weather.

Strong winds meant the aerial search for the men could not resume as expected on Thursday, police station commander Inspector Vicky Walker said in a statement.

The Americans, Kurt Blair, 56, of Colorado, and Carlos Romero, 50, of California, are certified alpine guides, according to the website of the nonprofit American Mountain Guides Association. New Zealand authorities have not released the name of the Canadian climber at the request of his family.

The men flew to a hut halfway up the mountain on Saturday to begin the climb and were reported missing on Monday when they failed to arrive to meet pre-arranged transport after the climb. Hours later, searchers found several climbing-related items believed to belong to the men, but there was no trace of them, police said.

The search for the men stalled on Tuesday and Wednesday due to worsening weather conditions in Aoraki, also known as Mount Cook, with heavy rain and snow forecast. Walker had previously hoped work would resume on Thursday, but said conditions that day were unsafe.

Aoraki has an elevation of 3,724 meters (12,218 ft) and is part of the Southern Alps, a picturesque glacial mountain range that runs the length of New Zealand’s South Island. The village of the same name at its base is a destination for domestic and foreign tourists.

The peak is popular among experienced climbers. Its terrain is technically challenging due to crevasses, avalanche danger, changeable weather and glacier movement.

More than 240 deaths were recorded. on the mountain and in the surrounding national park since the early 20th century.