Competitors in Saturday's Coast to Coast multisport race were forced to dodge falling rocks as they ran.
Just under 800 competitors were registered for the event, from as far afield as Sweden and Zimbabwe.
The 243km race traverses the South Island from Kumara Beach on the Tasman Sea to Sumner Beach on the Pacific Ocean.
Competitors cycle 140km, run 36km - mostly across the Southern Alps - and kayak 67km through the Waimakariri Gorge.
Race operations manager Dale Coulter says the organisers were forced to change the course several times because of torrential rain and strong winds on the West Coast.
He says a contingency course was set up, replacing the mountain run with a run along the state highway.
However, competitors were still forced to dodge falling rocks dislodged by the rain as they ran.
"Across the island and the elements, and you know, you're at the mercy of the weather. We had some rock falls on the mountain run through the state highway, but no-one got hit," said Mr Coulter.
The river kayak was replaced with a cycle to Christchurch followed by a paddle down the Avon, but due to strong winds on the estuary, the last kayak leg was replaced with another bike ride.
Walker and Miazga win again
The defending champions Gordon Walker and Emily Miazga triumphed again in the one-day race.
First to finish in the one-day event was defending champion Gordon Walker, with a winning time of nine hours, 43 minutes.
Aucklander Walker, 37, crossed the finish line five minutes ahead of Dougal Allan.
Miazga was the fastest woman and fourth overall, behind the third place-getter Brent Sarten.