A Clay County accident Wednesday afternoon resulted in injuries.  The Highway Patrol reports Laura Umstead, 55, of Lawson, was travelling westbound on County Road 166 and came to a stop sign, but was unable to stop due to the slick road conditions.  The vehicle slid through the stop sign and crossed paths with a northbound vehicle on US 69 Highway, driven by Richard Barrett, 24, of Excelsior Springs.  Umstead sustained minor injuries and was transported to Excelsior Springs Medical Center for treatment.