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.
- Water levels across the NWT remain very low.
- These dry conditions began during the summer and fall of 2022 and have persisted through the end of last year (2023) largely due to hot and dry conditions in northern Alberta and British Columbia, and the southern NWT over the past two summers.
- The Slave River was below average over the summer and remained that way through fall and into winter.
- Great Slave Lake remains at the lowest water level ever recorded for this time of year.
- Water levels on Great Slave Lake have been increasing recently as combined inflows from the Slave River (sourced in part from outputs from the W.A.C. Bennett Dam in British Columbia) and other smaller rivers exceed outflows to the Mackenzie River.
- In the month of January, snowfall amounts - which are presented as snow water equivalent (SWE) - across the territory ranged between average and below average.
- Snow water equivalent (SWE) is the amount of water that remains when snow is melted. The accumulated amount of SWE over a winter provides a strong indication of how much water will be available to flow to rivers and lakes in the spring. SWE values account for the density of the snowpack and are therefore not the same as snow depth values. For example, heavy and wet snow has a higher SWE than light and fluffy snow.
- Accumulated SWE for the entire winter up to now has been below average in Hay River and Fort Simpson, about average in Fort Smith, Yellowknife and Norman Wells, and above average in Inuvik.
- The SWE data presented are accumulated values from Environment and Climate Change Canada gauges at airports. The GNWT’s Department of Environment and Climate Change will conduct end-of-season snow surveys near the end of March to get a better understanding of SWE across the NWT.
- Water levels on Great Slave Lake and the Mackenzie River this coming spring/summer will be impacted by snowpack volumes and spring rainfall amounts in northern Alberta and British Columbia.
- SWE data from these locations show that the snowpack is well below average so far this winter