Heavy rain is expected to move into southern Alberta over the next few days and the city is taking preventive measures to reduce the risk of flooding.

The rain started falling lightly on Wednesday and the cloud cover is expected to increase overnight.

The big change will come on Thursday and Calgary could see between 20 and 30 mm of rain before the sun comes out on Saturday.

The city has dropped the water level in the Glenmore Reservoir to accomodate the flow from upstream of the dam to reduce the risk of flooding. The lower levels are exposing debris and that is making it dangerous for boaters.

"It's bringing in the silty water, the debris, which is the trees and all of that, so now we create a lot of safety hazards and we can't get to people," said Doug Bruneau, from Glenmore Reservoir Services.

Environment Canada has issued a rainfall warning for the Crowsnest Pass, Pincher Creek and Waterton Lakes National Park areas.

The agency is predicting total rainfall amounts to be between 60 and 90 mm and say the potential is there for local amounts to exceed 100 mm.

Residents who live near the Highwood River in High River always have an eye on the water levels when the forecast calls for excessive precipitation.

The town has created a High Water and Flood Resources page on its website and will be posting regular updates on water levels.

Calgary Five-Day Forecast from the SkyWatch Weather Centre:

  • Wednesday: Cloudy, chance of late day showers, high 16
  • Thursday: Rain, high 10
  • Friday: Rain, potentially heavy rain, high 11
  • Saturday: Mix of sun and cloud, chance of showers, high 15
  • Sunday: Mix of sun and cloud, high 16

For the latest conditions, visit the CTV Calgary SkyWatch Weather Centre.

(With files from Vickie Chase)