Climber falls into Mount St. Helens volcano after snow cornice collapses underneath him

A rescue operation to find the climber had to be suspended after high winds dislodged rocks in the crater and made footing unstable for search personnel.

Skamania County undersheriff Dave Cox said a helicopter which does contract work for the U.S. Geological Survey spotted the climber on a steep slope near the bottom of the crater, but was unable to pick him up because of the winds and whiteout conditions.

Rocky Henderson, of Portland Mountain Rescue in Oregon, said: 'There are always overhanging cornices of snow this time of year, and unless you look carefully you may not notice that there is nothing but air beneath you.'

The rescue was launched after an emergency mobile phone call yesterday afternoon. The caller told dispatchers that the climber was approximately 5ft from the crater's edge when the snow cornice collapsed.

The man had a climbing partner who did not fall, according to Mr Cox. They have not been named.

A U.S. Coast Guard helicopter also had to abort a rescue attempt because of the high winds.

The condition of the climber is unknown, but he was heard blowing an emergency whistle yesterday afternoon and authorities last heard from him just before darkness fell.