DENVER Several crashes and weather-related closures snarled traffic in parts of metro Denver on New Years Eve night.A band of snow fell in the north metro area around 9 p.m. and quickly dissipated, leaving icy spots and snow-packed roads in Thornton and Brighton. Both cities are on accident alert due to the conditions.Southbound Interstate 25 in Northglenn was shut down because of icy conditions. Police said those conditions caused semi-trucks to slide, blocking traffic lanes. Traffic was being diverted onto E. 120th Avenue.Colorado Department of Transportation shut down the westbound lanes of Interstate 76 in the area due to safety concerns. There is no estimated time for its reopening.And in the south metro area, multiple crashes involving several vehicles forced the closure of Interstate 25, just two miles south of the Castle Rock Exit.There is no word on injuries or when the lanes will reopen at this time.