It keeps a "hybrid reserve" at the bottom. It can still run in hybrid vehicle mode even when EV range gets to 0. I will admit to not having figured out all the numbers. There are others on the Clarity forums that are working on those details.
As for my range right now, it's been crappy since it's so freaking cold here (also in CO). I am getting about 33 miles before the engine has to kick in, but I have also been driving "normally" and enjoying full heat and preheating the cabin before every drive, even off the charger. So, I could probably hypermile, etc and get a little more. I'll do some real tests once the temperature gets back to a reasonable level.
Honda still hasn't gotten it 100% right. The Guess-O-Meter on this car is a hot mess. They also haven't given the dealers any chargers. They delivered the car to me with almost no EV range remaining. I had driven it two days before, right off the truck and had used most of the battery range that it was shipped with. Bought it that Saturday night but they couldn't deliver until Monday due to needing to complete the prep. I naively expected that they would at least plug it in for a bit before delivery, but no dice. I told the dealer they really have to get a J1772 installed because the thing is not nearly as fun to drive when the EV battery is out of range. They explained that it had a "full tank" to which i had to roll my eyes. They really broke the bank on the fill of the 7 gallon gas tank. I did get really nice, free, all-weather floor mats though.
On the other hand, the car is super comfortable and really nice inside. It drives really well. It's no Model S, but it's making me very happy. I've just never had a Hybrid, so the dissonance between the expected engine pitch and what it actually makes is still a little odd. Having your engine rev up out of sync with where your foot is on the pedal is like dancing to the wrong music, but I guess I'll get used to it.
In other news, do you still have your Model 3 reservation? Sounds like non-owners are getting orders in now.