At this time of year, Silver-haired Bats in Washington State are usually in hibernation. On the west side of the Cascade Mountains they may rouse briefly during periods of warmer weather during the winter, but they mostly remain dormant. It's likely that this bat was disturbed from his winter roost and ran into trouble when he was unable to quickly find alternate shelter.
He will spend the remaining winter months in care at the PAWS Wildlife Center. We are housing him in an unheated building so he will be able to continue his hibernation, but his enclosure contains food and water in case he chooses to rouse and feed on warmer days.