I am entirely flummoxed by this event. I was the last person to drive Mera, and there wasn't a crack in her windshield when I parked her in our heated garage. Later inspection showed no hint of any impact that might have been the source of the crack; it's a simple line that meanders its way about eight inches up my windshield. That's it.
Most likely, it's due to the cold snap we've been in, and perhaps even the temperature difference that Mera's exposed to when leaving the heated garage. The windshield has been hit by a few stray shards of gravel over its lifetime. While none have left a mark, I'm certain that one or more of them weakened the area enough for the cold to finally crack it.
That said, it's still pretty strange.