Recent novel, a teen in Australia surviving after comet/meteor impact devastates the world

Question

E-book, probably read in the last year or two. Probably written in the last 10 years. Seemed to be first in a series.

A comet or small asteroid is reported to be making a near miss to Earth. But as the time draws near, its changed to reporting it was actually going to hit all along.

Story is told from the perspective of a teenager (last year of school, or just graduated) who's parents were away on an isolated retreat and don't hear the updated reporting.

His town survives the near misses (pretty sure there were multiple impacts as it broke up. (Europe, Middle East, India, Indian Ocean and Australia) He lived in Western Australia, and the tsunamis from the ocean impacts destroy most of western Australia coastal cities/towns. Half of his town gets flooded.

Believe the story was written as journal entries, as he describes trying to survive in the heavy ash fallout from the impacts, and scrounging for supplies to protect himself and his house.

Eventually he gets a housemate, (the popular girl in school who never really noticed him) and builds a homemade hover craft to escape the town. They plan to head east to get away from the ash, and other residents who are becoming desperate and dangerous as supplies start running low. The book covers about a 1 year period, and he is stocking his hovercraft as the book ends. (Cant remember if left town before the book ends, but I think he does)

Answer 1

If you're right about Adelaide being involved, it could be Apocalypse: Diary of a Survivor by Matt J. Pike.

“I guess it was inevitable – the end of the world we know – the end of humanity.

Finding out early was a gift, surviving impact night was a miracle, living to tell the tale, well, that was the price I will pay, forever.

There’s no going back now.”

Award winning author*, Matt Pike, takes you on a journey to the end of the world and beyond, as told through the eyes of an Australian teenager, who records his experiences day by day in a survival diary. From the social chaos in suburban Adelaide in the lead-up, a night of total global catastrophe and the aftershocks as community and humanity crumble around him – the world changes forever. What’s left is a place where the conditions can kill you just as easily as the other survivors.

Everything our teenager relied upon for survival in the pre-disaster world falls apart – utilities, community, environment – the only things that can keep him alive are his resources and resourcefulness.

This review mentions his parents being away on a trip when the event happens (as well as his brother). This review mentions a hovercraft.

FWIW, search terms of site:goodreads.com post apocalyptic australia hovercraft journal

Answer 2

Could this be Life as We Knew It by Susan Beth Pfeffer?

Miranda’s disbelief turns to fear in a split second when a meteor knocks the moon closer to the earth. How should her family prepare for the future when worldwide tsunamis wipe out the coasts, earthquakes rock the continents, and volcanic ash blocks out the sun? As summer turns to Arctic winter, Miranda, her two brothers, and their mother retreat to the unexpected safe haven of their sunroom, where they subsist on stockpiled food and limited water in the warmth of a wood-burning stove.

Told in journal entries, this is the heart-pounding story of Miranda’s struggle to hold on to the most important resource of all--hope--in an increasingly desperate and unfamiliar world.

What does not match, of course, is the sex of the protagonist, and I haven't found proof it's set in Australia other than the book coming up with a search for novel teenager australia meteor post apocalyptic.