Even if you can't see an "impact star", the most probable cause for the cracks in your windshield is an impact with a hard object. If you can get your car to an auto glass repair shop before the cracks start spreading, there's a possibility that they can repair the cracks instead of having to replace the entire windshield.
Good luck!
The windshield is pretty tough stuff, so no way a ten pound cat could hurt one, even if you threw him at it. As to the freezing, it is more likely that you 'punchured' the glass while trying to scrape it.
If your car is parked in a warmish garage over night, say, and you drive out into a sub-zero blast of cold air, it will happen - it happened to me.
Rust
IMPACT my friend, IMPACT. Something hit it, you run defroster and it spreads, rapidly.
I have 2 cracks in the windshield. 1 is an inch long in middle and another is a one inch crack on the inside of the windshield. Both are hairline cracks with no impact stars of any kind.
I have 2 theories on why it might have happened....
1. my 10 pound cat likes to walk on my windshield so maybe he caused it.
2. few months ago windshield was frozen over and i used the cars heater and wipers to remove it and maybe that caused it.
Do either make sense or are there theories?
And does the new car warranty cover this? It is close to expiring. If not how much would it cost to repair?
