Snow and Ice Response

420 miles of city streets and 73 miles of multi-use paths are regularly plowed by the city and its partners when it snows. The city prioritizes emergency access routes, major arterial streets, and access to hospitals, schools, transit and critical infrastructure, as well as neighborhood streets with steep slopes.

When the city’s transportation system is impacted by snow and ice, our highest priority is to ensure safety and maintain emergency response capability. The interactive snow map shows which routes are cleared first.

• Primary Routes are key arterial roadways, including emergency access routes, major arterial streets, access to hospitals, schools, transit and critical infrastructure, neighborhood streets with steep slopes and the multi-use path system.
• Secondary Routes include remaining arterial and key residential streets which need service because of steep grade, shading, emergency access routes and school access.
  • Both primary and secondary routes require several passes before they are completely clear of loose snow. This is because turn lanes, multiple lanes and on-street bike lanes also need to be cleared.
• Conditional Routes contain residential roads that have been selected based upon critical connections for multimodal travel or school access, as well as steep or shady roads.
• Conditional Residential Routes are plowed when there is eight inches or more of snow and the temperatures are forecasted to be below freezing for three days.

Primary routes are plowed every 2-4 hours, secondary routes every 3-5 hours and conditional routes every 6-8 hours (when conditional residential routes are cleared it can be 10-12 hours). Timeframes may change based on conditions, traffic, time of day the storm starts, snowfall rate and staffing resources

Like other Front Range communities, the city does not typically plow side and residential streets since the resources and staff required to cover the 100s of miles of residential roadways is well beyond what can be funded. In most cases, motor vehicle activity and the sun will make most residential roadways functional before city plows can get to them.

With more significant snow events, once primary and secondary routes are relatively clear (travel, turn and bike lanes and bus pullouts), resources can be reallocated to residential streets. This brings its own set of challenges. Many local roadways are narrow and large city trucks can only clear a single center lane, causing large amounts of snow to be piled against parked cars and creating snow walls across driveways. This can make it tough for people to access their vehicles or the road. Most residential streets are driven on prior to resources being available and plow trucks will only be able to clear loose snow and apply de-icer to intersections. Packed snow will remain on off-route streets even after trucks have plowed the street.

The city began its conditional residential street plowing program in 2014, incorporating select streets that were prioritized based on an analysis of residential street slopes and shade. This program is funded from a 2013 voter-approved tax initiative that provides additional transportation funding from 2014 through 2030.​ When the forecast calls for eight or more inches of snow or three days of temperatures below freezing, the city deploys trucks to plow residential streets in predetermined areas with steep slopes or a lot of shade (see map). However, if Boulder experiences significant snow followed by several days of below freezing temps, the result can be layers of packed ice, and the city's equipment can't break up packed ice.

A 2013 voter-approved tax initiative provided additional funding that allowed the city to plow select residential streets in areas with steep slopes or ample shade after storms with eight inches or more of accumulation and/or prolonged periods of forecasted below-freezing temperatures.

Like other Front Range communities, the city does not typically plow residential streets and sidewalks after every storm for several reasons:

• The resources and staff required to cover the scope of this effort is well beyond the current Snow and Ice Response program budget. Funding this level of response would take resources away from other essential city services.
• Since most residential streets are narrow, plows can only clear a single center lane, which causes large amounts of snow to be piled against parked cars and creates snow walls across driveways. As a result, it is difficult for people to access their vehicles or the road.
• In most cases, vehicle activity and the sun make residential roadways functional before city snowplows can get to them.
• Adding route mileage to clear snow from residential streets would also see more environmental impacts of increased snow and ice response – air quality, emissions, water quality and storm water infrastructure. Our level of response must be balanced with the city’s commitment to its climate goals .

1. Streets and multi-use paths

   The fastest way to notify city staff is via the button at the bottom of the Report Snowy / Icy Streets page. You can also leave a voicemail at 303-413-7109.

2. Sidewalks

   Use the button at the bottom of the Sidewalk Snow and Ice Report Page you can also call Code Enforcement at 303-441-3333.

The team will inspect the area and will service depending on conditions and after prioritized streets and multi-use paths are cleared. If Boulder experiences significant snow followed by below freezing temps, the result can be layers of packed ice, and the city's equipment can’t break up packed ice. Multiple reports for the same location aren't necessary.

Like most communities, city property owners, managers and tenants are required to keep sidewalks adjacent to their property clear of snow and ice within 24 hours after snow stops.

It is the responsibility of the adjacent property owner, manager and tenant to clear a five foot path on curb ramps and crosswalks within 24 hours after it stops snowing.

There are over 80 miles of multi-use path systems and 73 of them are cleared edge to edge once per day during and immediately after it snows by the city and its partners. For the remaining paths, it is the responsibility of the property owner, manager and tenant to clear the full width of the path, or a width of at least five feet on paths abutting their property within 24 hours after it stops snowing.

Bus stops are typically located within city right-of-way and are not considered part of the sidewalk nor subject to city code (BRC 8-2-13). Approximately 20% of over 550 bus stops in the city are cleared of snow through maintenance agreements between the city and RTD based on available resources. RTD clears snow at 57 bus stops, city contractors at 38 locations and Shovel-A-Stop program volunteers at approximately 20 locations.

View the map depicting locations of RTD and city snow removal at bus stops.

The city and its partners clear 73 miles of multi-use paths as part to prioritize multimodal transportation. Multiple passes of these areas are typically needed before they are completely clear of loose snow. Each pass takes approximately 12 hours.

In heavy storms, snow from adjacent travel and bike lanes can be pushed from roads onto sidewalks. This is understandably frustrating for adjacent property owners and people walking but is impossible to avoid with heavy snow accumulations. When there is no area between the sidewalk and the street, staff must choose between fully clearing a travel or bike lane and impacting an adjacent sidewalk. Typically, staff use what space they can to open as much of vehicle and bicycle lanes while keeping as much of a sidewalk clear as possible.

During winters when Boulder gets a large volume of snow, packed snow will remain even after trucks have plowed the street. It is important to note that plows and snow clearing equipment move snow from one place to another instead of removing it entirely. If Boulder experiences significant snow followed by several days of below freezing temps, the result can be layers of packed ice, which the city's equipment isn’t designed to remove.

Sometimes snow may block driveways after city plows clear streets and paths. This can happen when storms produce large amounts of snow. This is especially true when the snow holds a lot of moisture, as it can create large balls of wet snow that moves away from plows.

The city began the practice of plowing snow to each side of the road before 2020, which can sometimes leave a a windrow, or row of snow, in front of driveways. There are tens of thousands of driveways on Boulder plow routes, making it nearly impossible for drivers to stop and clear each driveway entrance for two main reasons. First, safety is a concern, as plows have limited rear visibility, and clearing each driveway would require the driver to back up, putting children, animals and other vehicles at risk. Second, for the city to provide the most efficient and cost-effective snow response, continuous movement is required.

During winters when Boulder gets a large volume of snow, packed snow and ice will remain on off-route streets even after trucks have plowed the street. Plows and snow clearing equipment move snow from one place to another instead of removing it entirely. If Boulder experiences significant snow followed by several days of below freezing temps, the result can be layers of packed ice, and the city's equipment can’t break up packed ice.

Snow crews often must conduct multiple passes of areas before they are clear of loose snow. Even after multiple passes, normal travel conditions cannot always be maintained during winter storms and snow occasionally may be present, especially when temperatures remain below freezing for extended periods of time.

Plow drivers position the blade in float to clear snow from city streets during and after storms. The optimal weight of down pressure is set to manufacturer recommendations to avoid vehicle and roadway damage. The blade may appear to be above the street surface, but this is actually the plow riding on top of packed snow. Sometimes plows will keep their blade up to avoid removing anti-icing materials recently applied from another driver when traveling to and from their assigned routes.

City code (B.R.C. chapter 8-5) prohibits work in the public right of way without a permit, and the city does not issue permits for private parties to plow public streets. The one exception to this rule is the Knollwood subdivision because of how their annexation into the city was structured. The ordinance is intended to regulate work activities within the public right of way, and to protect the integrity and operation of the transportation system.

Yes. There is no city code provision that prohibits an HOA from plowing a private street.

When conditions allow, roads and paths are pre-treated to help reduce the buildup of snow and ice. Snow crews may also apply an anti-icer before a storm to minimize icy road conditions. If a storm starts as rain for multiple hours, pretreatment is ineffective because rain dilutes it and washes it off roadways.

While pre-treatments help reduce buildup of snow and ice, they do not prevent it entirely. Sometimes snow melts across the road and causes intermittent icy spots, snowfall rates are too intense for de-icing materials to be effective, or the effectiveness of de-icers has been reduced by snowfall before a plow truck can get back to that spot.

Depending on the weather, the city uses several types of anti-icers and de-icers:

• Salt Brine is a pre-treatment that helps reduce buildup of snow and ice
• Ice Slicer RS, a granular de-icer, is made up of complex chlorides that dissolve over time
• Meltdown Apex, a liquid de-icer, is a magnesium chloride solution, a plant nutrient and soil stabilizer that is less corrosive than other de-icing products

The city strives to sweep all primary and secondary streets and on-street bike lanes within three days of the end of a snowstorm to remove any surplus materials.

The city uses several types of anti-icers and de-icers, including Salt Brine, Apex Meltdown and Ice Slicer RS. All products are designed to minimize the impact of snow and ice on vehicles and work as freezing-point depressants. Using these products helps minimize impacts to air quality, as no sand or other traction materials are used, which can increase air particulate pollution.

The department’s 15 large plows all use modern diesel engines that meet state air quality requirements and are fueled by biodiesel.

The city has a total of 21 snow and ice control vehicles :

• 15 heavy vehicles for snow removal on major roads
• Four small vehicles to clear bike lanes, collector roadways and priority residential streets
• Two small vehicles and a specialized piece of equipment dedicated to multi-use paths

Snow crews are split into two 12-hour shifts and perform snow and ice control around the clock until the storm event is over. Then, crews operate on a typical 8-hour schedule.

• On-road operators and fleet mechanics are on 12-hour shifts. Shift changes occur at noon and midnight.
• Off-road operators are on 12-hour shifts. Shift changes occur at 4 a.m. and 4 p.m.

Funding for the city’s Snow and Ice Program comes from the city’s Transportation and Mobility budget. Visit the city’s budget web page to learn more.

Staff managing snow and ice control have a clear protocol in responding to storms.

• Days Prior:
  • The storm is tracked and if conditions allow, roadways may be pretreated.
  • Fleets are prepared.
• Hours Prior:
  • Snow shifts are called.
  • Materials and routes are assigned
  • The snow phone line is activated to receive public calls and requests for service.
• Storm Start:
  • Operators are on the road.
• Storm Start + 4 hours:
  • Operators are on the road.
  • Most primary and secondary routes have been serviced once.
  • Floater routes are more than halfway complete.
  • Multi-use paths are being serviced.
  • If it is actively snowing operators focus on keeping main lane(s) open.
    • De-icing materials are applied (most likely to intersections, hills and turn lanes).
  • If the storm slows or stops, on-road operators begin addressing turn lanes or pockets.
    • De-icing materials are applied as needed.
    • Clean up begins.
  • Operators may have recently or will recently return to the shop to reload materials.
  • Depending on the storm (accumulation, time of day and length of the storm) the city may use contractors to clear select bus stops, cross walks and multimodal connections.
    • This can occur multiple times through and after a storm or can occur once after the storm if the storm is short and brings little snow accumulation.
• After the Storm:
  • Snow operations continue long after the storm stops to complete routes.
    • For some of primary and secondary routes, this includes opening center turn lanes, turn lanes and a portion of on-street bike lanes.
    • Depending on the amount of snow the entire width of the bike lanes may not be open to prevent pushing that snow onto the adjoining sidewalk.
    • Opening a majority width of multi-use paths (this takes two passes after the snow stops falling).
  • Crews may go back to normal hours once the above is completed.
  • Activities that occur after the dedicated routes are completed include:
    • Removal of snow (in extreme cases, snow may be hauled out of the city).
    • Ice cutting with a road grader on areas where road drainage is impacted, or ice needs to be cut from dedicated routes.
    • Staff begins to remove ice at some crosswalks and bus stops by hand.
    • De-icing continues as needed and as conditions allow.
    • Staff begins filling potholes.
      • New potholes may appear after extreme temperature swings, moisture, freezing and thawing.
  • Depending on the storm, crews may respond to off-route requests.
  • Equipment is emptied, cleaned and repaired.
  • Materials are inventoried and refilled as needed.
  • A full team storm debrief is held to discuss challenges and opportunities.