Avista: Cause of Post Falls Dam crane accident still unknown

POST FALLS — A crane operator at the Post Falls Dam is recovering from multiple arm surgeries following an accident that occurred during construction Oct. 29.

"For some reason, the crane operator lost control of the load and the crane flipped over during the lifting operation," said Avista's David Howell during a Post Falls City Council meeting on election night. "We currently don't know what the cause of that was."

During the Post Falls City Council meeting Tuesday, Avista Utilities provided additional details about the crane failure Oct. 29 as well as a timeline for the reopening of Falls Park.

The accident happened while contractors were attempting to install steel structures, called bents, in the Spokane River. 

"In this case, we were very fortunate. The load landed across the river and the boom landed on the spillway," Howell said. He said things would have been much worse had the crane damaged a different area of the dam.

The incident occurred during a multiyear modernization project to replace power generation equipment that dates back to 1908. The dam's powerhouse generates enough energy to power approximately 12,000 homes. Avista uses the spillway to manage Lake Coeur d'Alene's water levels in summer and handle spring runoff.

The current phase involves installing a cofferdam — a temporary structure that creates a safe, dry work area for rehabilitation work. This requires placing multiple steel structures along the riverbed to create a temporary bridge for crane access.

Recovery efforts have been swift. Using a second crane, workers removed the damaged crane's boom in three pieces Monday, followed by the main body Tuesday. While all crane components have been cleared from the river, one remaining bent still needs to be removed and replaced this week.

The accident damaged the dam's middle gate operating system. Multiple agencies, including the Federal Energy Regulatory Commission's dam safety team and third-party structural consultants, have conducted inspections alongside Avista's internal engineers.

Avista officials announced Falls Park will reopen by Monday and said they are reviewing their emergency notification procedures for similar incidents.

    A contractor was injured Oct. 29 after a crane tipped over at the Post Falls North Channel Dam Spillway.