Data collected by scientists with the territory’s Environment and Climate Change department show water levels remain low in most rivers and lakes. Great Slave Lake’s level is lower than below average levels last year.
Data collected over the month showed precipitation and temperatures were also low.
Scientists reported that the spring melt was delayed in April.
“Water levels and flow rates remain very low across most of the NWT as we head into freshet. the spring melt is delayed compared to normal,” said the report’s authors.
While water levels were low as of April 27, with snowpacks above normal in the south, water levels could rise as temperatures rise.
Scientists also cautioned that level sensors can be influenced by ice formations, so the level readings should be interpreted with “caution.”
The data was collected up to April 27. Environment scientists compared water level measures recorded across the territory that go back about 100 years.
The data showed that water levels at the Great Slave Lake continue to be “well below average,” which was defined as being below the 10th percentile.
The water level measures from the Great Slave Lake were even lower than the level recorded this time last year and last year the level was also below average.
Another major lake in the territory showed similar trends.
“Great Bear Lake remains at its lowest water level for this time of year and is similar to the level recorded at this time last year,” said scientists in the report.
Similar trends persist with rivers in the territory.
Last month, data showed that the Slave River was below average for this time of year. Scientists said currently, the Slave River continues to show water levels below average for this time of year.
Below average was defined as within the 10th to 25th percentile range.
This could change soon as spring break up begins southwards, especially with snow pack or water equivalency measures higher than average in the south this season.
“Upstream of the Slave River, on the Peace and Athabasca rivers, break-up is underway,” noted the researchers.
The spring water outlook report showed snowpack accumulation was “higher than normal” in southern and western areas of the NWT, northern Alta., northern B.C. and the southeastern Yukon. However, snowpack accumulation measured lower than normal across most of the North Slave and Sahtu regions.
Last month’s report found that level measures collected from the Hay River showed that the water level was well below average for this time of year.
Scientists said Hay River water level remains very low, well below average for this time of year. They said the river has not yet shown ice movement or significant water level rise.
Data showed that water level the Liard River is “well below average.” At the mouth of the river, water measured below average for this time of year.
“Liard River has not significantly risen in the upstream reaches as of yet,” said the scientists.
Last month, the Mackenzie River’s water level, recorded at a number of stations along the river, showed levels “well below average” for this time of year.
According to the latest data, that has not changed.
Climate change researchers have reported the low water levels are the result of extreme drought conditions going back to the summer of 2022. The conditions have persisted through 2023, 2024 and 2025. Scientists reported that while water levels have shown some recovery, it has mostly been limited to smaller rivers and lakes in the territory.
While last month the Peel River showed average levels, the most recent data shows the water level is currently below average for this time of year.
There were some “notable exceptions” to low water levels including the South Nahanni River, which like last month, showed levels well above average.
The Mountain River and Dubawnt River showed levels “well above average” and the Hoarfrost River showed “record high” levels.
The Coppermine River, the Lockhart River and Taltson River had average water levels. The Hoarfrost River, also among the smaller rivers of the Great Slave Lake basin, showed above average levels.
Average was defined as within the 25th to 75th percentile.
The report’s authors said data collected in April showed temperatures were “well below average” in southern regions, “generally below average” in central areas and “average” in northern NWT.
Data collected during the month of April showed “lower than average precipitation” across most of the territory, said the researchers.
Scientists predicted that temperatures will rise this coming week, with nighttime lows above zero degrees Celsius and daytime highs “in the teens” around the Hay River basin and Liard River basin.
They estimated “generally average temperatures” especially in northern and eastern regions.
The report noted that precipitation data was primarily collected and managed by the federal Environment and Climate Change department but supplemented with GNWT climate station data.
Scientists reported “low confidence” in precipitation predictions of “near-average precipitation” for the territory. They added there could potentially be “a tendency” towards above-average precipitation in the Beaufort Delta and Sahtu regions.
