Roughly half of Bainbridge Island was without power late Wednesday afternoon after electricity was knocked out to nearly 4,000 homes and businesses.

Puget Sound Energy said the cause of the outage is under investigation.

The outage area now extends from the southern tip of the island northward to the Grand Forest.

According to PSE’s online outage map, a large swath of downtown Winslow, all the way east to Highway 305, is without electricity.

The total number of PSE customers affected as of 5:35 p.m. Wednesday was estimated at 3,879.

PSE hopes to have the power back on by 7:30 p.m. Wednesday.