Examining the need for anti-icing technology in the winter sports sector
Ice-jacking and hard rime are not phrases commonly heard among the skiers and boarders of the world’s winter sports resorts, and that’s not necessarily a bad thing. Both are examples of issues with ice that can cause havoc with equipment such as ski lifts and towers.
Ice-jacking caused the partial collapse of a gondola tower in Canada in 2008, leaving many passengers trapped in freezing temperatures for many hours. Some of the cabins dropped over nine metres as the lines sagged due to the collapse, causing minor injuries but it could have been far worse. It took over twenty maintenance staff a full twenty-four hours to both repair the tower and check every other structure at the resort. Ice-jacking is where water seeps into structures (in this case the gondola tower) and freezes, expanding and in rare cases causing the cracks to rupture.
This is just one of a range of icing issues in areas that host winter sports. ‘Hard rime’ is a white ice that forms when the water droplets in fog freeze to the outer surfaces of objects (a common phenomenon in colder climbs). It is often seen on trees atop mountains and ridges in winter, when low-hanging clouds cause freezing fog, but will form on any surface, including ski lifts and towers.
The resort of Mt Ruapehu in New Zealand is particularly susceptible to rime icing. The mountain sticks up at the centre of the North Island and is exposed to moisture-laden air and a maritime climate. When wind combines with 1 to -1 degree temps, any structure in the way of the wind cools down and ice forms on it rapidly. Ruapehu gets the biggest rime ice anywhere in the world, and as a result following a storm the lift towers and chairs are often loaded with tonnes of ice. How do they get the lifts turning? Good old-fashioned elbow grease – hitting the ice with a bat (!)
They have to de-ice all the way through each storm cycle (often in high winds and low visibility, making the job hazardous), because if they didn’t the ice build-up would become too much and damage the infrastructure. Often the ice builds up so quickly they are faced with the de-icing equivalent of painting the Forth Bridge – they have to start over again as they are finishing up. Another issue is when the storm clears; should there be a period of sunny weather it can cause water to run under the ice, destabilising it with potentially deadly ice-fall – it has been reported some of these ice lumps can be the size of small fridges.
Another issue concerns the sensitivity of safety monitors and switches; each tower has these and they can become damaged in ice storms. Chipping hard ice from around this sensitive equipment is tedious and time consuming but must be done with care in order to assure safe operations once the lift is started again. There is also a considerable safety check that occurs once a lift is brought back online after de-icing. (That’s why you may see a lift running with chairs, but no passengers). Other resorts, such as Perisher in New South Wales, Australia, suffer from the same issue. (It should be pointed out this isn’t just an antipodean problem, as resorts in the Alps and Norway have reported similar issues).
The upshot of all these scenarios is that icing continues to be a challenge within the winter sports industry. Climate change is also adding to the problem as conditions are far more unpredictable now, meaning ice storms can hit at unexpected times followed by unseasonal warmth, or heavy precipitation succeeded by extremely freezing temperatures.
To date there has been no real breakthrough in developing de-icing or anti-icing technology to help alleviate or prevent these issues; however there are several projects underway examining ways in which to combat them. The ICELIP project (commercial name Icemart®) – led by a consortium* of British-based organisations and funded by Innovate UK – are focused on the development and commercialisation of a new, passive ice-repellent coating that prevents ice formation and adhesion without the need for active ice-management. It incorporates functionalised nano particles into an aviation-certified film forming matrix and could provide ski resorts with an answer to the challenges posed by ice build-up.
* TWI Ltd, CAV Systems, LSBU, Innvotek, BAE Systems, Opus Materials Technologies
