She thanked Powell for being best friends with her for 10 years, in that time they were attached at the hip, Brewer said.
"Thank you for encouraging me to be crazy with you and not care what anyone else thought.
"You were the brightest of characters and could cheer up anyone. I'll miss your sense of humour and cracking jokes."
A funeral will be held for Powell next Monday at St Patricks Church in Napier.
Heaven had gained a "very special angel", Brewer said.
A second teenager was critically injured during the crash and remains in Wellington Hospital.
Powell and the second teenager had been schoolmates at Sacred Heart College in Napier.
The loss of Powell had deeply affected staff and students at the school, Sacred Heart principal Maria Neville-Foster said.
"We are deeply saddened by the loss of Ava. She was a much loved and respected member of our school community.
"Our thoughts and prayers are with her family at this time."
The injured woman was transferred by air from Hawke's Bay Hospital to Wellington Hospital where she was reported to be in the intensive care unit.
On Thursday a spokeswoman for the hospital said the "patient's family has asked for privacy" and was unable to provide a condition update.
The 3km stretch of highway was closed to traffic for more than six hours during the night but was reopened about 6am.
