U.S. 12 impassable at Milepost 143 due to flooding, WSDOT says December 9th, 2015 Andrew Villeneuve Core Topics The Washington State Department of Transportation reports that U.S. Highway 12, a key cross-Cascades route, is impassable between Packwood and Naches (milepost 138 to milepost 183) due to multiple slides. This WSDOT photo shows some of the damage, which will require serious repair work. This WSDOT photo provides another view of the washed-out roadway at Milepost 143 on U.S. Highway 12. Related