The Last Days series:

The Last Day on Earth: 

The Last Day On Earth - High ResolutionSometimes Lucy Black wished the governments had never admitted the asteroid was coming, and that everything they’d used to attempt to steer it off course had failed. Hadn’t admitted it would be catastrophic, and that it wasn’t just going to burn up in the atmosphere. Hadn’t confirmed that it was bigger than the one that had wiped out the dinosaurs and that they were probably all going to die.
That was two months ago.
Today is the last day on Earth.
The Last Day on Earth is a novella of 20,000 words, or approximately 70 pages.

Available in ebook and paperback:

The Long Road Home: 

R.M. Allinson (1)

The world has just found out that it’s going to end, with a huge unstoppable asteroid hurtling towards the planet. Claire is in Toronto with her two young sons. Her husband, Tom, is on the other side of the country and must find his way home in an increasingly chaotic landscape.

This is a parallel novel to The Last Day on Earth that follows Lucy’s sister and brother-in-law.

A short novel of 50,000, or approx. 220 pages.
Available in e-book and paperback.