Illecillewaet’s flow remains “near-normal” despite blockage

This aerial view shows the extent of the avalanche that has partially blocked the Illecillewaet River. You can view two more photos at the bottom of this story. Photo courtesy of the City of Revelstoke

By David F. Rooney

A team of experts were to overfly the scene of that blockage of the Illecillewaet River Wednesday, says a public notice from the City of Revelstoke≥

According to the notice, which you can read in its entirety below, water flows in the river appear to be near-normal.

The river was partially dammed by a major avalanche that occurred near the Lanark snow shed on the Trans-Canada Highway about 10 am Tuesday morning.

Emergency Program Coordinator Gerry Silva told City Council’s Committee of the Whole Tuesday afternoon that while there is no reason to panic, evacuation notices are being prepared — just in case.

“We are prepared to react if necessary,” he said, adding that “we are not in imminent danger.”

The avalanche was classed as a 4.5 and occurred about 45 kilometres east of Revelstoke. The snow shed is 400 metres outside of the west boundary of Glacier National Park. The pond that has collected behind the mass of trees, debris, snow and ice partially damming the river was (as of Tuesday afternoon) about 250 metres long, 150 metres wide and five metres deep, Silva said.

He said he understands that similar dams have occurred in the past on the Illecillewaet with little or no damage to Revelstoke. However, he recommended that as a precaution anyone living near the river pack one bag (per person) with enough clothing for 72 hours. If you don’t know what to pack, please go to the emergency services website. There you will find information about what you may need.

The City’s Emergency Operations Centre at City Hall is now in standby mode. The Columbia Shuswap Regional District’s emergency services personnel have contacted residents at Albert Canyon and Greely about the nature of the potential threat.

Public notices are being issued through the news media and, should a threat occur late at night, police and fire department vehicles with loudhailers will alert people.

Here is the text of the public notice posted on the emergency services website:


1200 hrs January 19, 2011

The City of Revelstoke advises the public that despite a blockage of the Illecillewaet River near the Lanark Tunnel, the river continues to flow at near-normal rates and a flood surge is unlikely.

However, today a helicopter with technical experts will fly over the blockage and the river downstream of the block to confirm that the blockage will dissipate naturally and will not pose a threat downstream.

In addition the CPR will watch and give early warning of any developing threats along the Illecillewaet River. It should be noted that we have been advised that a flow incident at Lanark Tunnel will take approximately 11 hours to reach Revelstoke.

Last night at 1800 hrs our EOC was downgraded to standby but staff have been assigned to keep a monitoring watch.

A further update will be released by the City of Revelstoke if the status changes.

Updates on the Lanark Slide will be posted online at

Here are two additional photos of the avalanche:

This aerial view shows the extent of the avalanche that has partially blocked the Illecillewaet River. Photo courtesy of the City of Revelstoke
This aerial view shows the debris that blocked the highway and tumbled into the the Illecillewaet River. Photo courtesy of the City of Revelstoke