Dramatic pictures from the Catlin Arctic survey team
A Devon woman leading an Arctic survey testing the thickness of the ice has described seeing a massive crack open up underneath the team's tent.
Ann Daniels, from Whimple near Exeter, is with two other adventurers testing the ice and acidity of the sea for the 2010 Catlin Arctic Survey expedition.
The crack emerged as the team were having breakfast four days into the expedition, which started on 6 March.
Nothing was broken, although the explorers were left a little shaken.
Ms Daniels is heading across the icy waters of the North Pole with photographer Martin Hartley and ex-marine Charlie Paton.
Mr Paton said: "We heard a crack, a few bangs and then suddenly the ice started to break apart.
"It all happened very quickly and was unlike anything I've experienced before."
Ms Daniels said: "It happened during breakfast, so the tent was full of equipment and our sledges were outside.
"We had to decide quickly which side of the crack we were going to try and stay on and quickly rescue all of the kit to ensure no lasting damage was sustained."
The team has also experienced fast-moving ice, large amounts of open water, ice floes splitting and rucking up, massive pressure ridges and ice boulders.
They are determined to continue their journey, collecting samples to assess the impact of carbon dioxide emissions on the oceans.
Mr Hartley said: "We're at least a week away from resupply, so it would have been disastrous to lose anything at this stage of the expedition.
"In fact the thought of being left without a tent in this extreme environment makes me shiver more than I already am."