The May Water Supply Outlook shows conditions are on track to be much better than those seen last year, with strong mountain snowpack conditions and multiple spring snowstorms bringing back much-needed moisture to most corners of the province.
“Most of Alberta is heading into the summer season in a much better situation than we’ve seen in recent years. Strong river flows, full reservoirs and additional mountain snowmelt still to come are all good news for communities, agricultural producers and the many industries that depend on a reliable source of water. However, we are carefully watching conditions in the far south and stand ready to take a more active water management role, if needed.”
River volumes are generally expected to be greater than those seen in 2025 and, in some cases, well above last year’s volumes. The May Water Supply Outlook forecasts river volumes through September that are above normal or well above normal for the North Saskatchewan, Red Deer and Bow River basins, and most parts of the Oldman River basin.
Strong snowpack conditions in the Rocky Mountains are the main reason for the positive outlook for river volumes in most of the province later this year. 92 per cent of mountain snowpack sites surveyed around the beginning of May had conditions that were above normal or well above normal, and 15 per cent had the highest snowpack conditions on record.
Alberta conducts mountain snowpack surveys monthly from Feb. 1 to June 1. From February through August, Alberta’s government uses snowpack and precipitation information to create a water supply forecast for 20 locations in central and southern Alberta, ranging from the North Saskatchewan River Basin, south to the Milk River Basin.
The exception to the positive news for most of the province is the outlook for the Milk River basin, which is expected to see river volumes that are well below normal through September. Forecasts for the Milk River are lower due to early season runoff soaking into the soil and not making its way into the river.
Due to the entitlements outlined in the Canada-U.S. Boundary Waters Treaty, irrigators in the basin can no longer draw water from the river. Household water use in the Town of Milk River is not impacted by an irrigation shutdown.
Alberta’s government explored options for additional water use flexibility on the Milk River that would support Canadian irrigators while still complying with the Canada-U.S. Boundary Waters Treaty and not harming irrigators on the Montana side.
Quick facts
- Water storage levels in major reservoirs in southern Alberta are in very good shape. Total storage is normal in the Red Deer River basin and above normal in the Bow, Oldman and South Saskatchewan River basins.
- Both mountain snowpack sites in the Red Deer River basin, eight of 14 Bow River basin sites, and three of eight North Saskatchewan River sites were in the top five highest years on record. Conversely, the one site surveyed in the Oldman River basin was the third lowest on record.
- Relative to normal winter precipitation levels, the area east of Lesser Slave Lake received the most precipitation, while the areas between Claresholm and Brooks and along the southern border received the least.
- Most snow monitoring sites located near the Milk River basin headwaters in Montana recorded May values in the lowest five years on record this past winter and the limited snowmelt runoff that followed occurred approximately one month earlier than the typical runoff period.
- During the irrigation season (April 1- Oct. 31), Canada is entitled to a 25 per cent share of the natural flows in the Milk River.
- According to the Canadian and American accredited officers who administer the Milk River entitlements:
- As of April 30, Canada was in deficit to the U.S.
- By early May, there were virtually no natural flows on the Milk River.
- Drought stage definitions in Alberta range from Stage 0 (no drought conditions) to Stage 5 (severe drought conditions).
- Drought stages for major river basins were last updated on May 11. More than half of Alberta’s major river basins are now at stage 0. The exceptions are:
- Stage 1 – Red Deer River basin
- Stage 2 – Oldman River basin, South Saskatchewan River basin, Buffalo River basin and Great Slave Lake basin
- Stage 3 – Milk River basin