Underwater slides threaten the energy transmission cable that connects Haines and Skagway.

Hydropower in the Upper Lynn Canal may be secure in drought, but the underwater cable that connects Haines and Skagway is not so secure.

Underwater landslides deteriorated the outside jacket of the underwater cable that transfers power from Skagway hydropower sources to Haines consumers. Pressure from slide material is further stressing the cable. Skagway Alaska Power and Telephone manager Darren Belislise says another slide could take it out.

“It is going to go out. When? Could it be tomorrow? Yeah. Could it be next year? Yeah. It is going to go out. Soon,” he said.

AP&T noticed the problem when fiber optic communications between power plants on either side of the canal went out on March 3rd. They launched an underwater remote operated vehicle last week to assess the damage.

Cable maintenance is tricky because the water is 300 to 1200 feet deep at the site of the damage. Belisle says that there are only about five ships in the world capable of laying power cable under the sea. Cables are job specific, so they would have to make a specialized cable.

In the summer, AP&T supplements Goat Lake with run-of-the-river power from Kasidaya Creek near Skagway. But in the winter there’s not enough water in the creek to use for energy.

Hydropower coming across the cable from Goat Lake is what gets Haines through winter when AP&T shuts Kasidaya down.

Haines has a diesel generator. Belisle says the infrastructure is older, but up to the task.

There’s enough power generated at Goat Lake to keep Skagway running on hydropower year round in the case of cable failure. But Haines would only get hydroelectric power during the summer. Belisle says Haines would have to run on more expensive diesel power in wintertime if the cable broke.

“We’re looking at that older infrastructure, looking at ways to make sure Haines is fully powered,” he said. “We just need to do a little proactive making sure we have more than what we need there.”

AP&T has not decided whether to repair or replace the cable. Any maintenance will affect the rate consumers pay. Belisle says all options are still on the table and that AP&T is working to keep costs down.

Correction: A previous version of this story incorrectly stated that Kasidaya power plant is on the Haines side of the Lynn Canal. Kasidaya Creek flows into the Taiya Inlet, a few miles south of Skagway.