What NWS says
An NWS page on snow ratios, read on 24 October 2026, says the ratio compares the water in snow with its depth; the old rule of thumb was 10 inches of snow for 1 inch of water (10:1), but “this is far from the norm”, and recent studies indicated that 12:1 might be more representative on average for the Upper Midwest. It adds that so many variables affect the ratio that a rule of thumb is usually off the mark and that the ratio can change dramatically within a snow event. Variables listed include the depth of the warm layer (warmer, closer to freezing, lowers the ratio), the amount of ice in the cloud versus supercooled water droplets, wind that fractures flakes and deep cold, which tends to raise it. A separate NWS briefing page shades 1 to 11 to 1 as wet snow, 11 to 20 to 1 as normal and 20 to 1 or more as dry.
Why this matters to the crew
| Snow type | What crews tend to notice | What to record |
|---|---|---|
| Wet (low ratio) | Heavier windrows, harder pushing, snow sticking to the plate | Pass depth, speed, any chatter or build-up |
| Normal | The usual workload | Baseline |
| Dry (high ratio) | Light snow that drifts and blows back | Drift locations, return passes |
A simple log
Three fields are enough to show whether snow type moves wear.
- Note the forecast ratio or category, and your own judgement of the snow.
- Record hours of plowing per truck and the edge wear before and after.
- After a season, compare wear per hour by snow type for similar routes.
What the log can and cannot show
- It can show whether your wet storms are harder on edges in your own records.
- It cannot isolate snow type from other factors such as ice, speed and pavement.
Limits
The NWS pages explain the ratio; they say nothing about plow edges. Any link to wear is your own finding.
Boundary: NWS pages explain the ratio and say nothing about plow edges; any link between snow type and wear is a hypothesis for your own records.
Sources and further reading. External references are dated; where a figure is quoted, the link shows where it came from.
National Weather Service (La Crosse, WI): What Are Snow Ratios? (undated page; read 2026-10-24) ↗National Weather Service (Gaylord, MI): Briefings – Winter Weather (snow to liquid ratio legend) (undated page; read 2026-10-24) ↗Why might an edge that clears packed snow leave a wet film in slush? ↗High-Impact Wear Parts: Material Strategies for Shock Loading ↗Carbide snow plow blades ↗Pavement Temperature Notes for Crews: A Simple Recording Card ↗Storm Debrief Template: Pavement, Treatment, Plow Passes and Edge Condition in One Page ↗Brine Tanks and Plow Trucks: Corrosion Management for Edge and Hardware ↗
