Calgary police are now investigating a serious crash southbound on Deerfoot Trail where, according to reports, one man is listed in critical condition.

The crash occurred at just before 6 a.m. on Deerfoot Trail and 24 St. S.E.

When emergency crews arrived on scene, they found seven vehicles are involved in the crash.

One person needed to be extricated from their vehicle.

That driver is listed in critical condition and has been stabilized by EMS.

One other person received minor injuries.

16 other people were involved in the crash and Calgary Fire say they've requested a Calgary Transit bus to the scene to help keep them warm.

Ten people have since been sent to hospital for treatment, including the man in life-threatening condition.

Adam Loria with Calgary EMS says that nine of the patients were transported to Rockyview and the Peter Lougheed Centre for treatment.

He says they all suffered minor injuries.

The man in life-threatening condition was transported to Foothills.

There is no further word on his condition.

Two lanes of traffic are getting through the scene, but the volume of traffic is so large that it is very slow.

Battalion Chief Larry Fisher says fire crews had to attend to an excess of 20 crashes through the night.

Police report that there were 11 injury crashes and 40 non-injury crashes from 7 p.m. to 9 a.m. on Friday.