When I finally got moving, I had confirmation of why I keep the snow tires on for 9 months each year. There was sleet and snow on the Divide, and driving was awful:
A "Chance of snow"
I dragged the bike up there but there was no chance of any sort of ride happening, so I got lunch and poked around the Dillon area a bit.
I scored some heavily-discounted used (good condition) Easton carbon handlebars with rise at Wilderness*. Lately I've suspected two things about my bike: my bars are too low, and my seat is too far back. The fact that I can't ride without hands and my front wheel seems squirrely are suggestive of this. I used to have no problem riding with no hands on my road bike, but my weight was over the pedals. If I can find a cheap zero-offset seat post I'll try it.
And a funny thing happened on the drive back: I was passing everyone.
Me, who drives the speed limit and sits in the right lane watching everyone in Colorado pass me by, was passing everyone else in sleet, snow, slush and rivers of water on the highway. It just didn't seem that bad. I wasn't even driving the speed limit all the time.
Note: on the west side of the tunnel, rain turns the tire grooves in the rightmost lane to a Slip-'n-Slide. Stay in the middle during rain.
* Wilderness has new owners, by the way. I had a minor scare when they didn't have a record of about $750 worth of store credit for me from ski gear sales. Ahhh! However, the new owner looked back at the history and found my records, and said I was OK. Turns out the previous owner "expired" the credit when they handed over ownership. I didn't even know my credit had an expiration date :\ Hooray for the new owner. I'm grateful.