The first team are expected to finish the gruelling Ten Tors challenge on Dartmoor this morning after a stormy night on the moor.
On Saturday more than 50 youngsters dropped out of the event with aches and sprains amid strong winds and stormy weather.
Car parks became unusable and a park and ride service was set up for parents and friends to greet competitors.
The event is being heavily monitored amid stormy conditions on the moor.
An Army spokesman said the drop-out rate was normal.
In a tweet it said: "Ten Tors update - 53 fall outs, just the usual sprains & strains. Raining off and on and pretty windy. It's called a challenge for a reason."
Changes have been made to the course this year to avoid crossing rivers where water levels are deemed too high for safety reasons.
Hundreds of young people from schools and colleges across Devon are taking part in the event.
Among those taking part are Exeter School, Isca College, Newton Abbot College, Coombeshead Academy, Teignmouth Community School and Teign Academy.
They set off on the epic trek from Okehampton Camp at 7am on Saturday.
The Ten Tors Challenge is also one of the biggest outdoors adventure events for young people in Britain today.
Some 2,400 youngsters aged between 14 and 19 took part in Ten Tors, with a further 300 youngsters with physical or educational needs taking part in the Jubilee Challenge.
