Final answer:
The ski piste is referred to as 'cement' on the BC coast when conditions cause the snow to become icy and hard, often due to a mix of precipitation followed by a freeze.
Step-by-step explanation:
On the BC coast, the term cement refers to ski pistes that have become particularly icy and hard, which happens when the snow melts slightly and then refreezes, resulting in a very firm and unforgiving surface. This can occur when there is a mixture of precipitations, such as rain, followed by a drop in temperature that causes the water to freeze on the snow's surface. These conditions make skiing more challenging and less enjoyable because the icy surface can be very slick and difficult to grip with ski edges.