San Francisco - An adventurous snowmobiler survived a 400- metre fall into the crater of Mount St Helens and was recovering well Monday in hospital, the Seattle Times reported.

John Slemp, 51, had parked his snowmobile at a safe distance and crawled out near the edge of a snow cornice to peek down into the crater of the active volcano.

The cornice gave way, sending Slemp plunging 35 to 70 meters onto the crater's inner slope. Luckily for him snow cushioned his initial impact, but his ordeal was just beginning.

Slemp started sliding down the inside of the crater for another estimated 400 meters. He initially tried to climb out, but loose snow carried him back down, so he crawled over to a steam vent to stay warm.

Meanwhile, his companions at the crater rim alerted authorities, and a helicopter rescue team extracted him. His suffered only one significant injury, tearing some knee ligaments. (dpa)