Gov. Bob McDonnell has declared a state of emergency in Virginia, as snow continues to pile up and knock out power to electric customers. By issuing the declaration Wednesday, McDonnell authorizes state agencies to identify and position resources to respond rapidly to emergencies. More than 1 foot of snow has piled up in Virginia’s Shenandoah Valley as state police scramble to respond to hundreds of crashes and utility crews worked to restore power to more than 170,000 customers.