Paramedics took an hour and a half to respond to a life-threatening emergency in Wolverhampton after getting stuck in heavy snow = 11 times their target for reaching the most serious 999 calls.
The incident in Penn in December was West Midlands Ambulance Service's slowest response to a 'Category A' life-threatening emergency in two years.
Figures disclosed by the service today show the alarming extent to which winter weather can threaten survival chances.
As well as tackling difficult driving conditions, crews were hit by a 30 per cent increase in 999 calls in December 2010. On Friday, December 17, when snow and ice crippled the region's roads, the service recorded the busiest day in its history.
Average response times to Category A calls swelled from five minutes and 53 seconds in April 2010 to seven minutes and 26 seconds in December. Both figures are inside the Government target time of eight minutes.
The figures released today relate the the calendar years 2009 and 2010.
Snow in December 2009 also had an impact, with one emergency call in Springhill, Wolverhampton taking one hour and two minutes.
John Hawker, an ambulance service spokesman, said: "The last two winters have been some of the toughest experienced by the ambulance service.
"Snow, ice, freezing fog and a huge rise in the patient numbers has led to challenging conditions for staff. Unfortunately, the treacherous conditions meant it took longer to get to some patients than we would normally expect."
Responses to Category B call-outs, defined as serious but not life-threatening, also soared from seven minutes and 43 seconds in April to almost eleven minutes in December. It took the service two hours and 47 minutes to reach one Category B emergency in Quinton, Halesowen.