Each winter, the City and County of Denver receives calls regarding snow-plow operations and ice accumulation in the gutters along the streets. The Department of Public Works responds to these inquiries in several ways.
While the Street Maintenance Division is directly responsible for snow and ice removal, these situations can also be an indication of other infrastructure issues, which can involve internal cooperation and coordination with several Divisions within the Department of Public Works.
These FAQs were developed to help residents understand the City and County of Denver’s policies and practices regarding snow and ice removal, the causes of ice accumulation, suggestions for prevention and possible solutions, and contacts to have the problem addressed.
Main streets, or most streets with stripes, are the priority for the Department’s fleet of heavy plows. These are the streets that carry most of the city’s traffic as well as emergency vehicles and public transportation. Denver also plows around schools to provide safe zones for children. For each snow event, the number of plows deployed and use of de-icing materials depends on weather conditions.
Residential plows will also deploy when enough snow has fallen and they can be helpful in clearing a path for motorists to get to the main streets. The small trucks do not carry de-icing materials. The residential plows take a single swipe down the middle of each side street; they do not bring the street to bare pavement, but improve drivability.
Unlike the Midwest and East Coast, Denver’s climate provides 300 days of sunshine each year. It is not uncommon for daytime temperatures to reach into the upper 30s and 40s and higher following a snowstorm, causing the snow to melt quickly. The snowmelt runs down the gutter in the street until it is collected by a storm drain inlet or catch-basin (the opening in the curb) that connects to the underground storm drain beneath the street.
Occasionally, Denver will experience an extended cold-spell or period where daytime temperatures are neither sufficient nor lengthy enough to entirely melt the snow. When snow in the gutter partially melts, then freezes at night or in the shadow of trees or structures before reaching a storm drain inlet, icing occurs. Shaded areas are particularly problematic, as pavement temperatures in shaded areas have been found to be about 20 degrees colder than areas exposed to the sun. Thus, repeated partial daytime warming and night-time freezing results in the accumulation of ice in the gutter.
There are many locations throughout Denver where snow and ice accumulates in the gutters. It is most common on the south side of east-west streets, but can also occur anytime that the gutter or street is shaded by structures, tall vegetation, trees or fences.
In areas where there is no tree-lawn between the curb and the sidewalk, the sidewalk is attached to the curb and gutter. Under prolonged night-time freezing conditions, the ice may eventually accumulate to the top of the curb and onto the adjacent sidewalk.
The picture below shows an area where the low winter sunlight is filtered by trees that have dropped their leaves. This keeps the street cool enough to allow ice to form and accumulate.
Each location is unique. Some areas require infrequent ice removal, while other areas require more.
Thus far, we have found it is more cost-effective to address these situations on a case-by-case basis, and you will need to call each time the ice reaches an unsafe level.
Storm drains are constructed based on criteria established to provide a standard level of flood protection during summer storms. In many cases, we have found that constructing storm drains and inlets are ineffective for solving icing problems. As shown in the picture below, these icing problems can prevail, regardless of the proximity of drainage inlets and storm sewers in areas of ice and snow build-up.
The City and County of Denver Department of Public Works’ Engineering Division reviews many of the repetitive complaint locations received by Street Maintenance Division on a case-by-case basis in order to determine if there are other cost-effective practical alternatives that would reduce the amount of ice accumulation. When such alternatives are available, they may be implemented based on priority and available funding.
In some situations, a storm drainage improvement may be planned for the area based on the City’s level of service for summer storm drainage. Once the project is funded and in design, our designers will, to the extent practicable, specify inlet locations to collect the summer storm runoff as well as collect winter daytime snowmelt before it enters a shaded location to reduce the amount of ice accumulation. When this is possible, it will help to reduce, but will not eliminate, the amount of ice accumulation.
As shown in the pictures below, in shaded areas it is not uncommon to see storm drain inlets between the patches of ice. In this case, the inlets are not effective in solving icing problems.
Sunken Curb & Gutter Sections
In other situations, icing in the winter occurs at the same location that there is a constant puddle of water in the summer due to sunken curb and gutter sections. These are reviewed for remediation by the Department of Public Works’ curb and gutter program based on priorities and available funding. If you notice that the curb and gutter in front of your home or business is sunk, precluding proper positive drainage, you may contact 3-1-1 to begin an investigation.
An effective proactive solution that property owners can implement is to apply de-icing materials to problem areas in advance of forecasted snowstorms. Placing de-icing materials on pavement before a storm makes snow and ice accumulation less likely and removal much easier. Some residents have found that also placing additional de-icer on the pavement after snow removal has been found to make subsequent ice accumulation from daytime melting less likely.
We also recommend that businesses and residents not push snow into the streets, where it can exacerbate ice formation in shaded areas. Instead, place the removed snow on lawn areas where available, or move it to a sunny location where it can melt; as long as doing so does not create other safety hazards.
The only system in place at the present time is our service-request system. Please contact 3-1-1 as noted in question 3 and request "ice blading."