Fierce winds, heavy snows and fears of an avalanche are hampering search efforts Tuesday to find a climber who fell into the crater of Mount St. Helens in Washington state.

Authorities planned to resume their search Tuesday for Joseph Bohlig of Kelso, Wash., who plunged 1,500 ft. into the volcano's crater after the snow on which he was standing gave way. But extreme weather conditions and falling rocks have temporarily suspended the ground search.

Skamania County Undersheriff David Cox said officials have asked for a military helicopter to help locate Bohlig, 52, who was climbing the volcano Monday with another man when he fell from the crater's rim.

Cox said the rescue effort was suspended Monday evening when high winds made footing unstable for search personnel.

One rescuer reached the floor of the volcano's crater, but had to abandon efforts to find Bohlig because strong downdrafts were dislodging rocks, Cox 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," said Rocky Henderson of Portland Mountain Rescue in Oregon, who has climbed to the rim several times.

Rescue efforts began when a 911 cell phone call was received early Monday afternoon, sheriff's officials said. The caller told dispatchers that the climber was approximately 5 feet from the crater's edge when the snow cornice supporting him collapsed.

A helicopter that does contract work for the U.S. Geological Survey spotted Bohlig Monday on a steep slope near the bottom of the crater but was unable to pick him up because of high winds and whiteout conditions, Cox said.

A U.S. Coast Guard helicopter also had to abort its effort to find the man because of the winds.

Bohlig was heard blowing an emergency whistle Monday afternoon, and authorities last heard from him just before darkness fell. Cox said his condition was unknown.

Mount St. Helens blew its top with devastating force on May 18, 1980, leveling 230 square miles of forest.

The climb to its crater provides outstanding views of the lava dome, blast area and surrounding volcanic peaks, according to the U.S. Forest Service. Most climbers complete the round trip in 7 to 12 hours, but the service's Web site warns people to stay back from the crater's rim because of its instability.

The Associated Press contributed to this report.