SPRINGFIELD – Storm damage forced the transfer of dozens of maximum-security, mentally ill inmates Saturday, leaving the Dixon prison locked down with emergency generators providing power and prompting the correctional workers' union to raise more questions about the practicality of Gov. Pat Quinn's plan to close penitentiaries in a severely crowded system.

The Department of Corrections transferred 78 inmates from Dixon to segregated cells at the maximum-security Pontiac Correctional Center after severe weather that rolled through north-central Illinois Friday night ripped up roofs and caused other "significant" damage, spokeswoman Stacey Solano said.

The prisoners went to isolated units at Pontiac because they are not "general population" inmates, Solano said. Anders Lindall, a spokesman for the workers' union, the American Federation of State, County and Municipal Employees, said those transferred were mentally ill inmates from a maximum-security Dixon wing.