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EMERGENCY INFORMATION

UPDATED: August 5, 2024

Chilcotin Blockage Situational Update
– 16:00 August 5, 2024

  • This morning, August 5, water began actively flowing over the landslide blockage of the Chilcotin River. At 09:00, August 5, water reached the downstream edge (toe) of the blockage.
  • At 12:30, the flow had increased to in the range of 2,000 to 3,000 m³/s. Downcutting of the landslide blockage occurred and the cut channel width is estimated as 80 m wide.
  • At 14:00 the leading edge of the breach water had reached the confluence with the Fraser River. Leading-edge water indicates the start of water level rise and is not representative of the peak breach height.
  • There is significant woody debris being mobilized in the Chilcotin and Fraser rivers (downstream of Chilcotin), and the leading edge of the water contains woody debris.
  • Staff on site have been moved to a safe distance away from the blockage.
  • Engineers and Geoscientists continue to monitor as the situation evolves.
  • Slope instabilities and other minor landslides have been noted in the upstream flooded area. There is an increased risk of additional landslides in the flooded upstream area.
  • Bank erosion has been observed along the Chilcotin River and is expected to continue during the event.
  • As the flood wave passes downstream, there is an increased risk of additional landslides and bank erosion. This is primarily focused on the Chilcotin from the blockage to the confluence. However, depending on breach timing there could be risk in the Fraser River from the Chilcotin confluence to Lillooet.
  • The breach continues to develop at a moderate pace, however at any point the breach development could accelerate. As the water levels decrease in the upstream area, the chance of rapid breach formation decreases.

For on-going updates and photos visit: https://gov.bc.ca/landslide

Background

  • A large landslide occurred on the Chilcotin river 30 km upstream of the Fraser River confluence late in the evening on July 30, 2024. Additional smaller landslides occurred during the evening of August 3 and the morning of August 4, originating from the top of the primary landslide failure. The new smaller landslides are contained primarily to the right side of the channel and preliminary reports show this has not changed the minimum overtopping elevation.
  • The landslide blockage was approximately 1000 m long (along the channel) and 600 m wide.
  • The river was completely blocked 16 km upstream on August 4.
  • As of August 4, slope instabilities and other minor landslides had been noted in the upstream flooded area.
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