Runners taking part in a previous Ultra Trail du Mont Blanc. Photo: akunamatata CC-BY-ND-2.0

One of the world’s toughest ultramarathons was halted yesterday because of severe weather.

The Ultra Trail du Mont Blanc had started on Thursday evening as runners and walkers set out on the 160km (100-mile) route around the base of western Europe’s highest mountain.

But organisers abandoned the race with about a third of the way in as cold and wet weather in the high Alps was deemed to put athletes at risk. A statement said: “High altitude weather in the mountains is not passable and not safe.”

The race was halted at St Gervais and the runners bussed back to Chamonix. A shorter, half-loop around the course – the Courmayeur-Champex-Chamonix race – was postponed but due to start yesterday.

The cancellation of the event, which top runners complete in about 20 hours, was the first in its seven-year history.

The UTMB attracts runners from all over the world and is considered the hardest running race in Europe. It involves 9,400m (30,840ft) of ascent and climbs to its highest point Grand Col Ferret at 2,537m (8,323ft) on the Franco-Swiss border.

The race, which is sponsored by The North Face, attracts 2,000 entrants each year. Catalonian Kílian Jornet Burgada won the event in 2008 and 2009.