An 85-year-old woman found comatose in her car in a Vancouver impound lot on Thursday has not regained consciousness and is now listed in grave condition, say police.

The car had been towed from a no-parking zone on Kingsway Avenue in East Vancouver on Wednesday.

Vancouver police spokesman Const. Tim Fanning said heavy frost on the windows had prevented the bylaw enforcement officer and the tow-truck driver from seeing the woman inside the car.

The unconscious senior was discovered on Thursday morning when a Busters Towing attendant scraped frost off the window of the car— nearly 21 hours after it was towed.

Fanning said the worker contacted police and called an ambulance, and the woman was rushed to hospital, where she is now in palliative care.

He said an investigation found no evidence of wrongdoing.

"Nobody did anything wrong in this case at all. It's very unfortunate, and, you know, we suspect it probably had something to do with a pre-existing medical condition."

Police did not release her name or where she's from.

City hall officials say they will review towing procedures internally and with the towing company.