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 – December 9, 2024

Current Status:

• Early winter water levels and flow rates remain very low across most of the NWT and, in many instances, are similar to those recorded last year at this time. Ice and freeze-up dynamics may cause spikes or gaps in water level and flow values, which may be seen in some of the figures in this report.
  • Great Slave Lake remains at its lowest water level recorded for this time of year and is equivalent to the level recorded at this time last year.
  • Flow rates on the Slave River this November were approximately average for this time year.
    • Cumulative flows on the Slave River for the year (i.e. adding up all the water that has moved through the river) are very low, but flow rates increased to average in November.
    • This was due to the higher-than-normal fall precipitation in the headwaters of the Peace River basin (northern British Columbia).
  • Flow rates on the Hay River are well below average for this time of year.
  • Flow rates on the Liard River are at their lowest recorded value for this time of year.
  • Flow rates at most locations along the Mackenzie River are well below average for this time of year.
  • Great Bear Lake reached the lowest level on record in November and flow rates on the Great Bear River are well below normal for this time of year.
  • Some rivers in the NWT have started to rebound from record low conditions in areas to the north and east of Great Slave Lake. Specific examples include:
    • Snare River (tributary to the North Arm of Great Slave Lake): Flow rates were the lowest on record for much of 2023 and early 2024 and are currently at the low end of average for this time of year.
    • Lockhart River (tributary to the East Arm of Great Slave Lake): Flow rates were the lowest on record in the fall and winter of 2023/24 and are currently average for this time of year.
    • Coppermine River (drains northeastern NWT and flows into the Arctic Ocean at Kugluktuk): Flow rates were the lowest on record in the summer of 2023 and are currently average 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.
• November precipitation across the NWT was generally below average, except Fort Smith, which received above average precipitation.
• November temperatures across the NWT were warmer than average for all communities except Fort Simpson and Norman Wells, where temperatures were approximately average.
• Water levels on Great Slave Lake and the Mackenzie River are strongly influenced by precipitation received in northern British Columbia, Alberta, Saskatchewan, and southern NWT.
  • Precipitation in the Great Slave Lake basin in northern British Columbia and Alberta has been approximately average this fall (Oct 01 to present), with some community variability.
    • Located near the headwaters of the Peace River, the community of Mackenzie, British Columbia, has received record-high cumulative precipitation this fall.
      • This region (the mountainous headwaters of the Peace River) usually receives the highest amount of precipitation in the Mackenzie River basin and is, therefore, an important contributor to water levels on Great Slave Lake and the Mackenzie River.
• Climate forecasts from Environment and Climate Change Canada (ECCC) for the next three months (Dec, Jan, Feb) indicate higher than normal precipitation for most of the NWT and the Mackenzie River basin.
  • The month of December has a high likelihood for above average snowfall in the NWT with an estimate of 5 to 25 mm more precipitation than normal (average precipitation values for December are usually between 15 to 25 mm in the NWT).
  • ECCC meteorologists have indicated that the strength of the La Niña system this winter will be weak and that the predicted above-average snowfall is likely not attributed to La Niña.