How we calculate the Hardpack Probability %
Each day gets a hardpack risk score based on 5 factors combined:
1. Fresh snow — Recent snowfall is the #1 softness factor. More than 8cm/day = very soft (powder), 4-8cm = soft, 1-4cm = moderate. No fresh snow adds to hardpack risk.
2. Freeze-thaw cycles — When the temperature crosses 0°C (above during day, below at night), the surface melts and refreezes into a hard crust. The wider the swing (e.g. +4° to -3°), the harder the surface.
3. Days since last snowfall — Each day without significant snow (>2cm) adds +6% to hardpack probability, up to 5 dry days (+30% max). Snow compacts under its own weight over time.
4. Snowmaking vs temperature — Snowmaking is context-dependent: on cold dry days (<0°C), cannons add snow volume and keep surfaces fresher (up to -8% hardpack). But when temps rise above 0°C, artificial snow is denser than natural and compacts into hardpack much faster (up to +18%). The worst combo is freeze-thaw + heavy snowmaking — gets an extra penalty.
5. Extreme cold — Very cold temps (<-8°C) without fresh snow create an icy surface crust, adding +10%. Very warm temps (>6°C) create slushy conditions instead of hardpack.
Reading the score: 5-25% Soft/Powder — 26-45% Some firmness — 46-65% Likely firm — 66%+ Hardpack/Icy