The key consideration is, always, safety on the snow for our guests. There are two aspects that have to be right before a run will open: the snow cover, and a Ski Patrol run assessment.
Snow cover, or more specifically, efficient snow cover, is critical. When there's been big snow falls, the snow will settle and 'ski itself in'. When there's middling snowfalls more needs to be done. The weather, particularly the prevailing wind, and the shape of the terrain dictate where the snow falls, as it doesn't fall evenly over the terrain. The groomers play a big part in relocating the snow to even out the coverage.
If there is some snow but not sufficient to open the run, the groomers will 'track pack', running over the existing snowpack without the tiller to break up the snowpack without grooming. The resulting rough surface will then catch and hold snowfalls, which can be relocated over the run.
Natural events can change the behaviour of snow deposits in specific areas. An example is Orchard, where there are still many dead snowgums. Normally the foliage of a healthy snowgum will catch snow and deposit it on the leeward side of the tree. Trees with no foliage can't do that - the snow is blown straight through them. At Orchard, this means more work to redistribute snow to ensure good coverage and to cover any potential problem areas, such as the creek line that leads down to and through the lift midpoint.
'Snow farming' is also used. Snow fences are also used to catch snow, which is used to fill in problem areas like bare patches, holes and creek lines. These fences can be permanent structures, or they can be temporary ones that are moved according to the weather and run requirements. Groomers also help with snow farming by creating 'windrows' or mounds strategically positioned on the runs to catch and hold snow for relocation.
Ski Patrol run assessment
Every run has both natural and artificial boundaries. Natural boundaries - think tree lines, drop-offs, embankments. Ski Patrol puts up the artificial boundaries just prior to the start of the winter season (often before there is any snow) and checks them again when there is snow on the run. Occasionally they might need to be relocated depending on where the snow has landed and how the run has subsequently been groomed.
Ski Patrol also checks known troublespots, such as creeklines and rocks, to determine the snow cover and ensure the run is safe. Depending on the nature and condition of the spot, they will erect warning signs or ropes, or may not open the run at all if it's too dangerous or obstructive.
Then there's the determination of the condition of the run itself. You might get good snowfalls from the north, which fill in the southerly slopes, then have a southerly come through a few days later and blow the snow back in the opposite direction. This isn't always a problem, but can result in slopes being scoured of snow.
Finally, once Ski Patrol is happy with the overall condition of the run, the groomers will run over it and Ski Patrol will conduct one final check, for a final confirmation that any signage and barriers are sufficient and in the right spot.
Then...it's all systems go! The run is open.
Which runs are open? Check here.