Snow Emergencies, Plows and the Edges of a Saint Paul Driveway

How a snow emergency unfolds

Saint Paul often declares a snow emergency after 3 inches or more, weighing air and road temperatures, the forecast, the type of precipitation and how much snow is on the streets. Once declared, it runs for 96 hours. At 9 p.m. on the first night, parking ends on the Night Plow Routes: arterials, downtown and one side of north-south residential streets, all signed, plus all of downtown whether signed or not. Those routes are plowed overnight, until 7 a.m.

At 8 a.m. the next day the Day Plow Routes follow, typically both sides of east-west residential streets and one side of north-south ones, until 5 p.m. Clean-up fills the rest of the 96 hours, with salting and push-backs where parked cars have since moved. Across all of it, the city runs about 80 plows and other pieces of equipment over 1,874 lane miles, and cars left on the wrong side of the street are ticketed and towed.

Where the plowed snow goes

Plows push snow to the side, and the city is plain about what follows: snow ends up at the ends of driveways and on sidewalks, and crews do not come back to clear driveway ends, because with 1,874 lane miles to open they stay focused on the streets. Plow drivers are trained to aim for the boulevard, the city-owned strip between the curb and the sidewalk. The windrow across the end of a driveway is the owner's to clear.

Where that snow can go next is limited by rule. Shoveling, pushing or blowing snow into the street or alley is not permitted, and the city's guidance is to store it on the property or have a contractor haul it away. Sidewalks must be cleared to their full width within 24 hours. On a narrow city lot, the only room left for a winter's worth of driveway and windrow snow is usually along the edges of the driveway itself, and that is where the trouble starts.

What that does to the edges

An asphalt edge is the weakest part of a driveway, because nothing supports it from the side. A snow bank sitting on it all winter keeps it wet, and each thaw sends meltwater across and under it. At MSP, pavement crosses the freezing line about 78 days a year, and March is the worst month with nearly 18 crossings on average, just as the winter's banks are melting. The water that soaks in along the edge freezes at night and pries the aggregate apart. By spring the edge has a crumbled lip and a gap where the lawn used to meet it.

Blades add impact. A shovel or snowblower scraping the same line every storm chips the edge, and a private plow working a driveway or an alley catches any raised lip with steel. At the street, the city's windrow lands on the apron, and that apron is concrete because Public Works does not allow asphalt in the right-of-way without its director's approval. On the asphalt side, the joint where blacktop meets that concrete is the seam to watch, because water collects there and the two materials move differently.

Salt plays a smaller part on residential blocks than many owners assume. The city says it does not typically salt residential streets, while arterials are pretreated with brine. Most of the salt on a residential driveway comes in on tires from the arterials and from the owner's own ice melt. The MPCA's reminder that a single teaspoon of salt permanently pollutes five gallons of water is a good reason to use less of it, and a sealed surface lets less of it soak in.

The alley side of the problem

Behind the house, the city is not involved at all. Saint Paul has never plowed, salted or sanded its alleys, and snow cannot be pushed from them into the street. Neighbors hire a private plow, usually through an alley captain, and in the city's 2019 study 36 percent of respondents said their alley was plowed after a 2-inch snowfall, while 12 percent said it was not plowed at all. The private blade pushes the alley's snow to the sides, which on many blocks means onto the aprons of garage pads that owners maintain themselves.

Those aprons take the worst of it: a blade striking the step between a paved pad and a gravel or oiled alley, a bank sitting on the apron into April, and every car turning across it. An apron that was sound in November can be broken at the lip by March. The alley driveway guide goes further into who owns which strip of pavement behind the garage and how the city's alley categories affect it.

What to do before and after the season

Most of the protection happens in fall. Fill cracks along the edges and at the apron joint before the first snow so meltwater has nowhere to go. Mark the edges of driveways and pads with stakes so the plow operator and the snowblower have a line to follow. Keep the snow bank on the lawn side where the lot allows it, and on the low side of the pad so melt runs away from the pavement rather than across it.

After the thaw, look at the edges first. A crumbled lip can be cut back and patched with hot mix once the asphalt plants are running in spring, and a sound edge can be sealed along with the rest of the drive in summer. Edge repairs are the kind of asphalt patching that stays small if it is done each spring and grows if it is left for three. For the wider picture of pavement care in this climate, the overview of Saint Paul driveway sealcoating lays out the numbers.

• Fill edge and apron cracks in September or early October, while nights are still mild
• Stake the edges before the first plowable snow
• Ask the alley captain whether the contractor runs a rubber or polyurethane cutting edge
• Pile snow on the downhill side, away from the garage slab
• Walk the edges in April and note every broken section before summer bookings fill

More from the blog

• The Real Sealing Season in Saint Paul, Month by Month