A heavy storm has brought a record amount of snow to the US city of Erie on Christmas Day, forcing officials to declare a state of emergency. <br/><br/>A total of 34in of snow blanketed the city and surrounding areas in the Pennsylvania state. <br/><br/>There was no respite on Boxing Day, with meteorologists registering a grand total of 60in over the two-day period. <br/><br/>Police warned motorists that "roads are dangerous and impassable", with a number of closures reported. <br/><br/>More snow is forecast today. The officials said the heavy snowstorm is the result of lake-effect snow – when cold air combines with lake water. The city lies on the shores of Lake Erie.<br/><br/>The National Weather Center Cleveland on Christmas Day registered a new all-time high for any single day, beating the previous record set in 1956. <br/><br/>The state's two-day snowfall record from 1944 was also shattered, as well as a storm total snowfall and a monthly snowfall. <br/><br/>Shops and childcare centres were closed. Some flights to and from the Erie International airport were also cancelled.