A driving instructor on her way to teach a speed awareness course pulled out to overtake and caused the death of a pensioner, a court was told.
Defendant Anita Corless, 58, had no memory of the manoeuvre and could not explain why she overtook with such catastrophic consequences.
House keeper Rita Wharton, 83, from Welshpool – was killed instantly inside the wreckage of her Ford Ka following the multiple vehicle crash on the A483 road between Welshpool and Pool Quay, in March 25.
Corless of Milford Haven Marina in South Wales – but at the time living at Bentham in North Yorkshire - admitted death by dangerous driving and was jailed for 16 months.
She was banned from driving for two years and eight months and must sit an extended driving test.
The court heard how she was in a line of traffic on a straight stretch of road but inexplicably pulled out.
There was insufficient room and she caused a five vehicle crash. Corless was severely injured herself.
Judge Niclas Parry said that no sentence could reflect the tragic loss of life but said it was intended to reflect the defendant’s culpability as the cause of the fatality.
There was no evidence to suggest that she was driving at anything other than a reasonable speed but her driving caused a significant risk of danger, he said.
It was, he added, a thoroughly avoidable fatality “which “must be marked by a custodial sentence”.
Victim Rita Wharton, 83, was head house keeper at The Hand and Diamond public house in Powys.
Her daughter Diane Dunderdale told in a victim impact statement how her mother was fit and healthy.
They worked together, they finished work that day and she told her mother “see you tomorrow” but within an hour she was dead.
“My mother was my best friend and my rock,” she said.