The driver of the minibus has been giving evidence at the inquests into the A7 deaths.
William Darling, a driver with Telfords, said he saw the lorry drifting towards him across the white line.
"The next thing I knew, I was picking myself off the floor"
The driver was showered with glass and knocked unconscious by the impact, and spent time in hospital being treated for arm and shoulder injuries.
The inquest heard how other passengers on the bus found Miss Rennie on the floor where '"she was already dead".
The driver of the lorry involved in the accident, Ian McQueen, also died.
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Three girls have been hurt after a stone was thrown through the window of the school bus they were travelling on in Carlisle.
Drivers are being urged to take extreme caution when driving this morning, as heavy snow covers routes across the ITV Border region.
The Met Office has issued a new amber weather warning for snow for the south of Scotland, and a yellow warning for parts of Cumbria.