Monday, March 9, 2015

Freeze-Thaw, Road Damage and Small Landslides

Despite the warm winter there was bit of very early cold weather that did do some road damage back in November in northwest Washington. A bad combination of wet weather followed by a hard freeze period is a bad combination for roads. During these periods counties will issue weight restriction rules to keep heavy trucks off of soft roads. 

This particular street in Bellingham continued to get water into the road bed and on the road itself days after the rains had stopped and the ground had frozen. The subgrade drainage has clearly failed here and the freezing water is starting to break up the pavement.

The freeze thaw process is also a driver of shallow landslides on shoreline bluffs. The expansion of water in the wet soil effectively peals soil off the bluff face that is already steep. I saw dozens of these slides during an early December trip before the mild winter weather took over this year.

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