Uncleared snow in Ukraine can make the world nervous, especially if it leads to the collapse of a roof at the closed Chornobyl nuclear plant, the sight of the catastrophic explosion in 1986. Authorities blamed a Feb. 12 roof and partial wall collapse at the ill-fated fourth unit on heavy snowfall. While emergencies services said radiation levels did not increase after the accident, 80 workers were evacuated from the site. Construction of a new shelter to cover Chornobyl’s fourth unit is scheduled for completion in 2015. A 30-kilometer exclusion zone remains around the plant
