"We don't have to get alarmed. It's under control." That was Baltimore Mayor Clarence H. Du Burns, speaking bravely on his first full day in office 20 years ago today. Light morning snow had intensified, and 2-inch forecasts were soon buried beneath a foot of snow. The season's first big coastal storm closed offices and schools. Alarmed commuters fled early into the flakes, only to clog the way for plows. Gridlock ensued. State police ordered 310 abandoned vehicles towed from area highways.