Effect of Blowing Snow and Snow Fences on Pavement Temperature and Ice Formation

摘要

Studies to identify specific causes of winter crashes in Wyoming indicated that the majority of crashes were associated with icy road conditions and that blowing snow was the dominant cause of icy roads in wind-exposed areas. The finding that 74% of all crashes over a 5-year period were associated with icy road conditions on a segment of Interstate 80 was illustrative and typical. The mass of blowing snow falling on the pavement with a 10 m/s wind (22.4 mph) was equivalent to a snowfall rate of 7.8 cm (3.06 in.) per hour, assuming a snowfall water equivalent of 10%, and the mass flux of blowing snow at 20 m/s (44.7 mph) was approximately twice that amount. The energy required for melting the blowing snow associated with the 10 m/s wind speed was nine times the average daily radiation received at Cheyenne, Wyoming, in December, and four times mat received in March. The effect of blowing snow on pavement temperature can be quantified using vehicle-mounted infrared sensors applying the techniques described. Examples show that the melting of blowing snow constitutes a major heat sink and that areas protected by snow fences can be 6℃ (10℉) or more warmer than adjacent unprotected road. These quantitative measurements explain the dramatic effect of snow fences on road surface conditions that have been previously reported, and they provide a compelling argument for mitigating blowing snow with roadside vegetation as well as fences.