Hard freezing weather in December and early January – combined with a quick thaw – caused extensive damage to roads as potholes sprouted across Whatcom County, city and county officials said.
Damage was more in the northwest part of the county, said County Engineer Joe Rutan. He said the ground had frozen to a depth of nearly 2 feet and it thawed from the top down, allowing the soft and flexible paving to “float” on the frozen ground below, rather than being supported by its substrate.
“After we’ve had a large freeze, if it warms up from the top down, the pavement is essentially floating on ice,” Rutan said. “The pavement has no structural strength.”
Heavy trucks, especially, cause roadways to crumble under such conditions, and county officials issued weight limits for roads on Jan. 15. Those restrictions were lifted Monday because the ground has thawed and drained.
An early December weather pattern brought sharply cold and dry air south from the Fraser Valley of British Columbia, keeping lowland Whatcom County temperatures at or below freezing through December and into early January. On Jan. 15, daytime highs rose into the 40s and the region warmed rapidly into the high 50s. At the same time, overnight lows edged above freezing.
Rutan couldn’t give an estimate on the cost of repairing roadways damaged in the recent freeze, but he said county officials plan to focus their summer repair efforts on the northwest corner of the county. He said more damage is possible if cold weather returns.
Most of the damaged roads are secondary roads, Rutan said. Major county roads are built to a tougher all-weather standard and usually don’t suffer such damage, he said.
“The roads that did have the damage tend to be lesser roads that at one time were gravel roads,” Rutan said.
In Ferndale, officials are still assessing the damage, said city spokesperson Riley Sweeney.
“We’ve had to close sections of roads because of the frost bubble,” Sweeney said.
Sweeney didn’t have a cost estimate for the damage, but he did say that Ferndale followed the county’s lead on weight limits and is now building its roads to all-weather standards to prevent ice damage.
Bellingham saw some potholes emerge with the thaw, said Eric Johnston, assistant director of the city’s Department of Public Works.
“Obviously, with any winter event, that causes damage to roadways,” Johnston said. “There are some potholes. It’s the damage you’d expect and nothing out of the ordinary.”
As with the county, Bellingham’s most damaged roads already were slated for repair this summer, Johnston said. The roads that suffered the worst damage were in rough shape before the freeze, he said. In general, he said urban streets are built differently from county roads, with thicker asphalt and different foundation.
Johnston said bad roads have surface cracks that hold water, and when it freezes, the ice forces pavement even more out of alignment. He said damage could be $30,000 to $50,000, but repair funds are in the city’s budget.