The Government of the Northwest Territories maintains water monitoring stations across the territory to keep track of water levels and flow rates in areas of potential flood risk for communities.

This information is provided regularly to territorial and regional emergency managers to help understand the status of waterways across the NWT in the lead-up to, and during spring break-up – the highest-risk period for floods in the Northwest Territories.

Technical Data

• NWT Water Monitoring Bulletin – September 6, 2024

Current Status –Territorial Overview

• Water levels and flow rates remain very low across most of the NWT, with little change observed in August. Some rivers and lakes have seen slight fluctuations, but there have been no significant changes. Looking forward, a decrease in water levels and flow rates is expected for September and October, as is normal for this time of year, when precipitation amounts are reduced and fall freeze up approaches.
  • Great Slave Lake remains at its lowest water level recorded for this time of year and is lower than last year. The water level has increased since the start of summer by about 12 cm.
  • Flow rates on the Slave River have increased in August and are approximately average for this time of year, although cumulative flows for the summer are still very low relative to average.
  • Flow rates on the Hay River are at their lowest recorded value for this time of year.
  • Flow rates on the Liard River are well below normal for this time of year, and cumulative flows on the Liard River have been extremely low this summer.
  • Flow rates at most locations along the Mackenzie River are well below average or at their lowest recorded values for this time of year.
  • Flow rates at the outlet of Great Bear Lake are below average for this time of year.
  • Water levels in the Mackenzie River Delta have slightly increased in August but remain low for this time of year.
• Low water levels continue to be the result of extreme drought conditions that began in the summer of 2022, and have persisted through 2023 and 2024.
• Cumulative precipitation so far this spring and summer has been well below average for NWT communities, apart from Inuvik, with well above average precipitation. Cumulative precipitation in Yellowknife is at its lowest value on record.
• August precipitation across the NWT was well below normal for nearly all communities. The only exception was Inuvik, which received approximately average precipitation.
• August temperatures across the NWT were much warmer than average, driving higher evapotranspiration rates.
• Low water levels on Great Slave Lake and the Mackenzie River are influenced by rainfall received in northern British Columbia, Alberta, Saskatchewan, and southern NWT.
  • Precipitation in the Mackenzie River basin in northern BC and AB has been approximately average so far this summer, with some variability between communities.
  • Average precipitation has not been enough to overcome the extreme drought and soil moisture deficit. Several months of above-average precipitation is needed to raise water levels.
  • As of August 25, 2024, BC Hydro started filling the Site C reservoir. The process is anticipated to take up to four months to complete. The filling of Site C is projected to have a relatively minor impact on our water levels compared to the
    effects of our current drought which caused water levels to drop significantly during
    the summer of 2023.
• Guidance from Environment and Climate Change forecasts suggests that most of the NWT will likely (greater than 40% chance) see above normal precipitation for the months of September, October and November.