Complex sentence: Kayla goes to the top of the peak and bravely snowboards down the mountain, as she is being recorded on T.V. But at the way down, she causes an avalanche and is buried under the snow.
Split into simpler sentences: Kayla goes to the top of the peak and bravely snowboards down the mountain, as she is being recorded on TV. But on the way down, she causes an avalanche and is buried under the snow.