Yeah, altitude was a contributing factor of why we didn't summit Elburt this winter. After doing some rock outside Denver, then driving to Ouray for a week of ice climbing (at 7,700 feet we did fine maybe even better...lol), we drove up to Leadville (highest incorporated town in Colorado 10,152 feet) to bag Elburt on one of our last days. While not a technical climb by any standard, apparently winter isn't necessarily mountaineering season in CO as many locals thought it unusual that we wanted to hike Elburt (and weren't skiers to boot). Anyways, we pulled into town at 7PM beat and while eating dinner I felt so out of it... almost high as everyone sounded like they were talking through a paper towel roll.
"Add Meatballs Sir?"
"What'd she say?"
"She said 'meatballs' and she' still standing next to you"
We stayed at a shady Super 8 and woke at 4AM to get an alpine start. The snow was just billowing down and apparently whoever is in charge of the trails isn't as kind to winter hikers as the AMC because we had to descend down to 9,000 feet for winter access, making the prospective gain a snowy unbroken whopping 5,440 feet for the day. We were supposed to start on an access road but we ended up on the Continental Divide trail because we followed the massive signs that said "Elburt Trail This Way" (silly us). After a while it started to become unclear which way to go, sparser vegetation, poorly marked trails, and it looked like the trail didn't get much use anyways. As the sun rose we both kept seeing blue spots and blotches around us we figured due to the altitude. I also had a horrifically upset stomach which we later learned was Mountaineers H.A.G. (didn't read that one in Freedom of The Hills) exhausted and with the weather worsening we turned around at 11,000 feet. In summer or under better conditions we couldve made short work of it. And yes, I had a map, actually I had two because part of the tricky access road/trail combo was on another map so we had to buy two huge maps (95% and 5% of the trail on the other) and hold them together. You'd think a road would be a significant marking on a map but it was a little faded line. Turns out the access road started 30 feet up from where we parked!
Now the training regime has been getting better. We did 14 miles almost 4,000 feet from Sawyer road up Carrigan and back in 6 hours (beat sunset). The Saturday before we got the Carters/Height almost 5,000 feet of gain in 7+ hours.