More than 130 mm of rain has fallen over portions of central/southern Alberta

Yellow-level rainfall warnings were still in place across central and southern Alberta early Tuesday as heavy rain continued to fall.

Since Saturday, a slow-moving low-pressure system (serving as the southwestern anchor of a blocking pattern in the upper atmosphere) has been grabbing moisture and mixing it with colder air and funnelling both against the eastern slopes of the Rocky Mountains.

In their 5 a.m. MDT warning, Environment and Climate Change Canada (ECCC) explained portions of central and southern Alberta had recorded between 40 to 120 mm of rain, with some areas in southwestern Alberta measuring more than 135 mm.

Those rainfall warnings were updated around 10:30 a.m. Tuesday to include only a small area west of Calgary, with the national weather agency explaining, “Since Saturday evening, 80 to 100 mm has been reported in the area so far, with one report of 150 mm. An additional 5 to 10 mm is expected today.”

By 11 a.m. Tuesday, the rainfall warning was dropped.

That same low-pressure system prompted a special weather statement for areas of southeastern British Columbia due to a heightened risk of flooding, landslides and/or washouts from the combination of heavy rain and snow.

“Total rainfall amounts will vary greatly across southeastern B.C. Highest rainfall amounts near 60 to 80 mm are possible over north- and east-facing slopes as well as communities and highways closest to the Alberta border. Up to 40 mm of rainfall is possible for areas further west.”

Cooler temperatures have proved helpful in this rain event, with some areas in the mountains seeing snow rather than rain. That fresh snow has helped to hold some of the winter’s snowpack in place rather than enhance melt rates.

Between some snow melt prior to Saturday and heavy accumulations of rain since, many waterways have still been dealing with increased volumes and faster flow rates. As of 10:30 a.m. Tuesday, there was still a flood watch for the Bow River near Lake Louise, and many areas in central and southern Alberta sit under high streamflow advisories.

Strong wind will continue to be a factor Tuesday, with wind speeds of 40 to 60 km/h expected in Calgary and gusts up to 80 km/h in some areas.

The combination of strong wind on trees sitting in saturated ground can increase the risk of trees falling on structures and/or power lines.

Water is pooling in some areas due to the amount of precipitation that has fallen over such a short period of time.

Stream banks should be avoided due to compromised integrity from erosion and slides, and vessels should stay off of rivers and streams because of the fast-flowing water.

In a weather summary Tuesday morning, ECCC shared rainfall totals recorded from May 30 to June 2, 2026 (at 9 a.m. MDT). Among them:

• Stavely—139 mm;
• Mossleigh—125 mm;
• Calgary — 70 to 100 mm;
• Edmonton — 75 to 100 mm;
• Lethbridge—99 mm;
• Medicine Hat—66 mm; and
• Red Deer — 61 mm.

The weather agency also noted higher elevations between Banff and Kananaskis saw between 10 to 15 cm of heavy, wet snow.

The rain will taper off on Tuesday and Wednesday, with areas like Calgary expecting another 5 to 10 mm of rain throughout the day.

The omega block that has been sitting over the eastern Prairies will start to break down over the next 24 hours and open things up for a more typical west-to-east pattern across the west.

Daytime highs will return to more seasonal values starting Wednesday, with highs in Calgary around 20 C by Thursday.

There is a slight chance of showers and/or mild thunderstorms in Calgary on Thursday and again on Saturday, but if there is rain, the accumulations should be minimal.