The past night had not been kind to Demelza's dormitory, and so she had decided to forget trying to sleep in the Common Room before the sun rose, grabbed some proper clothes and stowed all of her books and uniform into a large bag, which she then brought down to the Quidditch Pitch, and left in the changeroom with a protective spell.
Grabbing her broom from the storage shed, Demelza quickly took to the sky. She relied on flying to clear her head, and it wasn't that much earlier than she was frequently up. But when it came down to it, she had hardly slept last night. Her reaction times were not at their peak, her head was fuzzy, and flying wasn't fixing it.
Demelza flew in larger circles, avoiding obstacles, and feeling the wind in her hair. Normally, she would have remembered that the Whomping Willow hadn't been pruned, and she would leave it any extra wide berth. But Demelza wasn't focusing, so she assumed the pattern that had been her tradition since second year. It took her too close to the Willow.
As she flew, a smaller branch lashed out at her. She dodged to avoid it, but flew almost directly into a much larger branch. It made a loud 'WHOMP' sound, and Demelza, holding her broomstick, let out a scream of pain as she fell to the ground, feeling bones breaking as she landed awkwardly.