City crews were out cleaning up Friday morning after a major storm hit Edmonton Thursday night.

Edmonton Fire Rescue crews were kept busy during the deluge, which hit some areas much harder than others, rescuing drivers whose cars were swamped in underpasses along Yellowhead Trail.

Some drivers found themselves trapped on top of their cars as they waited for help.

In total, rescue crews were called out to 18 events, with the worst flash flooding happening along the Yellowhead at 121st,127th and 142nd Streets, and at St. Albert Trail.

Crews were also called out to help people whose basements were flooding.

Edmonton Namao Airport recorded 45 millimetres of rain, while 41 millimetres fell at City Centre Airport.

Southwest of Edmonton, Violet Grove received about 21 millimeters of rain.

The storm dumped up to 50 mm of rain in some parts of the city. And as homeowners deal with its aftermath the city is trying to figure out what to do next.

Drainage upgrades cost money

Edmonton has had 100 millimeters more rain than average this summer. Mayor Stephen Mandel says the city has to figure out ways to deal with water that pools quickly in heavy rain.

"That's going to take a lot of money — tens of millions of dollars to build different kind of reservoirs to take care of it and our department is coming up with ideas but it's going to be an expensive process," he said.

City officials recently estimated the upgrades could cost as much as $200 million.

"We’re trying to seek more funding for some of these upgrades and we will look at them and prioritize them. and try to get costing and solutions," said Derek Melmoth, the city's director of drainage services.

"Some of these solutions are not easy."

All the areas that caused trouble last night have been fixed and roads are now open.