06/18/2014 08:59 EDT | Updated 08/18/2014 05:59 EDT

Alberta flooding: Voluntary evacuation issued in Claresholm

Officials with the Town of Claresholm, an hour southeast of Calgary, are asking some residents to leave their homes because of overland flooding, as rising water levels have led to states of emergency in several southern Alberta communities.

The sewer system is also backing up and many homes are under water.

An evacuation centre has been set up at the Claresholm arena for any residents affected by the flooding.

Schools in the town are also closed, except for students writing diploma exams. Parents are asked to take those students to the arena, where buses will pick them up and take them to their schools.

Late Tuesday, the Blood Indian Reserve joined the list of communities that have declared a state of emergency. 

The reserve, 233 kilometres southeast of Calgary, joins:

- The Municipal District of Willow Creek.

- The municipality of Crowsnest Pass.

- Lethbridge County.

- The City of Medicine Hat.

The threat of flooding is expected to continue through Wednesday as Environment Canada issued another rainfall warning early in the morning for areas from Brooks to most of southern Alberta.

Environment Canada says a low-pressure system is expected to bring up to 70 mm of rain Wednesday in the southwestern foothills before tapering off Thursday morning. The total rainfall in that area may exceed 200 millimetres.

Further north and east, 40 to 60 mm have been recorded.

Less overall rain than expected

The provincial government's flood forecasters say much less rain fell overnight than forecast.

"While overnight there were some pockets of very intense precipitation and there has been some localized flooding, the rainfall has not lived up to expectations. It significantly less than we had predicted," said Katrina Bluetchen of Alberta Environment.

In Cardston, there are reports that Lee's Creek has overflowed and low-lying areas are beginning to flood. 

People in Coalhurst are experiencing flooded basements and sewer backups. 

The rainfall warnings do not include Calgary.