Skied Vail Monday with one son and Wednesday with two sons and my wife, and both days it felt relatively unsafe due to crowding on the few open slopes and lifts.
The amount of people on the mountain relative to the amount of mountain open is not safe for families currently. Perhaps this is often the case Thanksgiving week...don't know because I've never skied this week in Summit Co though I have skied here Dec-March for the past 30 years.
Specifically the catwalks and several of the greens are a mess as they form a logjam near the few open lifts, gondolas and some young men (100% of the perps I witnessed) are bombing them and narrowly missing seriously injuring or killing someone. My wife and I did our best to shield our kids skiing in front and behind them, but often someone would cut in between us in minimal space for no good good reason. By 2:30p we were all just ready to get off the mountain fully intact. I sent my wife and younger son down the gondola and should have sent my older son down with them too.
To be fair and accurate, the family ski area was nice and sparse, and several of the slopes were not too crowded (esp before noon), but you will inevitably hit the log jams near the lifts which are legit danger zone right now. Unless your kids are truly advanced skiiers, leave them behind. I rode Keystone on a board solo on Tues and had a blast, and that was far less crowded despite 12" of fresh powder.
Yes, you can always encounter the aforementioned at most any ski resort at most any time, but this is the highest density of reckless behavior in such close proximity to me and my kids that I've experienced in 30 years in Colorado.
I saw one teenage girl taken out pretty badly (her mom lost it with the guy) and another fool cut between my son, and instructor and his student, with inches not feet to spare, at ridiculous speed. The instructor hollered after him but he was gone...
As for Covid-19, my family all had it earlier this year, in northern Italy of all places (mild cases), so we weren't concerned about contracting or infecting anyone. If you are concerned about Covid-19, then know that you will be encouraged though not required to ride lifts with strangers, and you will be a couple feet away from other people for 15-20min in lift lines.
Anyway, I'll certainly be back to ski with the fam in Summit Co again, but probably not Thanksgiving week.
Be safe and Happy Thanksgiving!