Snow removal terms, explained in plain English

Weather and measurement terms

• Snowfall vs snow depth. Snowfall is the new snow since the last measurement, read to the nearest tenth of an inch before it settles, and it counts sleet too. Snow depth is everything on the ground, old and new, to the nearest inch.
• Trace. Snowfall that never reaches a tenth of an inch, or snow cover under half an inch deep. Reports show it as T.
• Snow-to-liquid ratio. Inches of snow per inch of melted water: the old rule of thumb is 10 to 1, and the National Weather Service office in La Crosse says about 12 to 1 is more typical in the Upper Midwest. Wet snow runs lower and weighs more per inch.
• Drift. Snow piled unevenly by wind, during or after a storm. Drifts can refill a cleared drive after the snow stops.

Service terms

• Trigger depth. The accumulation that sends a plow without a call. In Macomb County, residential triggers are commonly 2 inches and commercial triggers 1 inch.
• Push or visit. One clearing of the property. A long storm can need two, so how the second one bills belongs in the agreement.
• Event. One storm, as the contract defines its start and end, which matters when a second storm follows a day later.
• Bare pavement. A standard: plowed and treated until the pavement itself shows, which takes de-icing, not just a blade.
• Clear-by time. The hour a commercial lot must be usable, such as 7 a.m. It decides how much equipment a site needs.
• Windrow (plow ridge). The heavy ridge a road plow leaves across a driveway opening. In Michigan it is the owner's to clear, and it cannot go back into the road.
• Apron. The end of the driveway where it meets the street, where the windrow lands. Some crews also use the word for the slab in front of the garage door.
• Back-dragging. Dropping the blade at a garage door or wall and backing up to pull snow away, then pushing it clear, so snow is not packed against the door.
• Stacking. Piling snow in agreed spots, ideally where meltwater drains away from pavement.
• Relocation and hauling. Relocation moves existing piles within a property; hauling trucks snow off site. Both are commercial services, usually billed by time and materials.
• Return visit. A trip back to a stop that was skipped or blocked, or a second pass in a long storm.
• Cleanup pass. A final pass after the storm to widen cleared areas, push piles back and clear a ridge left by a late road plow.
• Route. The driving order a crew follows through a storm. Position depends on location and booking date, not on who calls.
• Dispatch. Sending crews out. Automatic dispatch means every property past the trigger is cleared without a call.
• Skip with reason. A stop marked not done, with the cause recorded, such as a car across the apron. A good system pairs each skip with a return visit.

Pricing and contract terms

• Per-push. A price for each clearing. Simple, but a long storm can mean two or three pushes.
• Per-event. One price per storm, however many pushes it takes, so the contract must define an event.
• Seasonal, capped or uncapped. One price for the season. Uncapped covers every event past the trigger; capped covers a set number, then bills per event.
• Time and materials. Hourly equipment and labor, plus salt and other materials. Common for hauling and irregular sites, and hard to budget.
• Tiered by depth. Prices that step up by snowfall band, such as 1 to 3 inches and 3 to 6. The contract should say who measures, and where.
• Zero tolerance. Keeping pavement clear throughout a storm instead of waiting for a trigger, usually with crews dedicated to one site.

Ice control terms

• Anti-icing. Spraying liquid de-icer, usually salt brine, before a storm so snow and ice cannot bond to the pavement.
• De-icing. Treating snow or ice after it has bonded, which takes more material than preventing the bond.
• Brine. Salt dissolved in water at about 23 percent by weight, the mix with the lowest freezing point. It works on contact and stays where it is sprayed.
• Pre-treatment. Any treatment before a storm; on pavement it usually means anti-icing. Pre-wetting is different: spraying brine onto rock salt as it is spread, so it sticks instead of bouncing.
• Refreeze. Meltwater freezing again, usually overnight after a sunny afternoon. It is how most black ice forms at home.
• Working temperature. The pavement temperature below which a de-icer stops being useful, also called the practical melting temperature. It is far warmer than the laboratory figure some bags print.

Commercial, insurance and records terms

• Certificate of insurance. A one-page summary of a contractor's policies, limits and dates. Get it before work starts and check the name matches the business you hire.
• Additional insured. Status that gives a property owner direct standing under the contractor's general liability policy for claims arising from its work. Standard in commercial snow contracts.
• General liability. Insurance for injuries and damage the contractor causes to others, such as a blade through a fence.
• Workers compensation. Insurance for the contractor's own injured workers. Michigan requires it of private employers that regularly employ three or more people at one time, or one person 35 or more hours a week for 13 weeks or longer.
• Site map. A drawing of the property marking stacking and no-stack zones, drains, hydrants, accessible parking and hazards, agreed before the season.
• Snow log. A record of each storm: weather, service times, treatments, conditions and inspections. Michigan injury claims can be filed for three years, so keep logs at least that long.