Pavement Temperatures and Effects: Importance of Pavement Temperature
Understanding how pavement temperature affects ice formation and melting is one of the most important factors in effective snow and ice control. Pavement temperature determines whether snow will accumulate on the pavement or melt on contact, whether snow melt or freezing rain may re-freeze or form ice, and help you determine if a deicer is needed and what deicer is appropriate for the conditions. Snow begins to accumulate and ice can form when pavement temperatures fall below 32°F. When pavement temperatures are at or above 32°F, snow can melt on contact even if the air temperature is colder.
Thaw and Refreeze
Winter often brings repeated freeze–thaw cycles. As air temperatures rise above freezing, pavement warms and snow and ice melt, especially on a sunny day. In the evening, pavement may stay above freezing even as air temperatures drop, leaving water on surfaces. When the pavement cools below 32°F, the water refreezes and creates slippery conditions. These freeze–thaw–refreeze cycles repeat throughout the winter.
Factors Affecting Pavement Temperature
Condition | Condition Details | Effect on pavement temperature | Explanation |
|---|---|---|---|
Pavement Type | Asphalt | Warming | Dark color absorbs more sunlight |
Pavement Type | Concrete | Slight warming | Light color absorbs less sunlight |
Weather | Sunny | Warming | Sunlight warms pavement |
Weather | Cloudy | Neutral to slight warming | Lack of or low sunlight |
Weather | Windy | Cooling | Wind can rapidly cool pavement, especially high winds |
Weather | Snow & ice on pavement | Cooling | Snow and ice can cool pavement |
Time of Day | Later morning to afternoon | Warming | Warmer air temperatures and sun warm pavement |
Time of Day | Evening to early morning | Cooling | Cooler air temperatures and lack of sun cool pavement |
Time of year | Mid-winter | Neutral to cooling | Colder air temperature and lower sun angle |
Time of year | Early & Late winter | Warming | Warmer air temperature and higher sun angle |
Subsurface | Early winter | Warming | Warmer soils may prevent/slow pavement heat loss |
Subsurface | Mid-winter | Cooling | Deep frost keeps pavement cold |
Subsurface | Bridges and overpasses | Cooling | No insulation - lose heat faster |
Shade | Shade caused by buildings, trees, hills, objects | Neutral to cooling | Blocks sunlight, deciduous trees let some light through |
Traffic | Heavy traffic | Slight warming | Tire friction, vehicle heat loss, ice breakup, convection can increase temperature |
Expand the dropdowns below to learn more!