The Illecillewaet River is dry after it was blocked by an upstream avalanche on the morning of Jan. 18. This long-exposure photograph of the river bed

Concern after avalanche blocks Illecillewaet River upstream of Revelstoke

REVELSTOKE — Concerns have diminished over the risks posed to Revelstoke by a blockage of the Illecillewaet River caused by a massive avalanche about 50 kilometres upstream of town Tuesday morning.

By Alex Cooper & Aaron Orlando

REVELSTOKE — Concerns have diminished over the risks posed to Revelstoke by a blockage of the Illecillewaet River caused by a massive avalanche about 50 kilometres upstream of town Tuesday morning.

“[The river] was damming up behind it but it seems to be flowing underneath, through and around,” Gerry Silva, Revelstoke’s emergency management coordinator told the Times Review in an interview Tuesday evening. “That means it’s not going to build up to some kind of huge, tsunami-type thing that’s going to coming thundering down and inundate the city.

“That really can’t happen.”

The natural, size 4.5 avalanche occurred on the Lanark slide path at around 10 a.m. Tuesday morning. It swept snow, logs and other debris over the Lanark snow shed, onto the highway and into the Illecillewaet River, said Jeff Knight, a spokesperson with the Ministry of Transportation.

Revelstoke’s emergency management program was mobilized as a result and Silva appeared at Revelstoke’s city council at 3 p.m on Jan. 18 to update them on the emerging situation. He told council the avalanche plugged the Illecillewaet River, causing pooling behind the blockage that was recently measured at 250-metres long.

From Illecillewaet Avalanche

Above image: This photo shows the debris from the avalanche looking uphill from next to the Lanark show shed. The avalanche came down the Lanark slide path Tuesday morning. Ministry of Transportation photo

“It’s not an imminent danger,” Silva told council, saying emergency operations were being mobilized “to make sure we are not taken by surprise.”

A declaration of emergency was sent out as a pre-caution, Silva said following the council meeting, and notices were delivered to people living in the Greeley area east of Revelstoke.

He said that monitors were finding the debris consisted more of snow than of trees.

“Our water experts are telling us that if anything did happen it would take 11 hours to move from where it is to where we are,” Silva said.

Silva recommended that residents be prepared in general by packing a bag. In the event that evacuations are necessary, Silva said responders would be mobilized to the areas to clear residents.

“Historically this has happened several times in the past and we expect to act the way it has in the past – that it will drain itself off and it will be a non-event,” he said.

When asked by council to summarize the situation, Silva said: “Optimistic, but damn well be prepared.”

The emergency operations centre is being at hosted at city hall.

The slide occurred while the highway was closed for avalanche control. It came down over the Lanark snowshed so not too much debris ended up on the road, said Knight. Further avalanche control work was carried about the Ministry of Transportation and the highway re-opened at around 5:30 p.m. according to DriveBC.

The situation will be updated on the Revelstoke emergency program’s website at www.revemergency.com.