I think i might have asked this once before, but it's still nagging me. I've been on a couple of mountains where the standard climb is after melt-out in late season, but if you are comfortable at fairly high-angle snow (~50 degrees) with axe and spikes AND don't mind a snowy approach hike, it's actually not a bad idea to hike early before the melt. I'm wondering if you think this is possible on the SW Couloir route. Say perhaps trudging in, with or without snowshoes, in mid-June on an average snow year like this year. Any chance that the Couloir would still have soft enough snow cover to make a reasonable unprotected climb???
I imagine it's entirely possible, though I've only been there late-season. I'd estimate most of the couloir is 40-45 degrees, and while there are a few choke points, I doubt they'd pose much issue. As long as you exit the couloir at climber's right at the top, it's only class 3, and as long as the ridge above is fairly snow-free, it should pose no problem.
I'd say the most challenging parts of an early season climb would be gaining access to the lower portion of the couloir from the top of the basin, and the challenges of crossing (probably fording, in this case) Sky Top Creek on the approach, as this was tricky in a few spots even in September in a high-snow year. You might be able to mitigate this by going the Aero Lakes route, but I'm not sure how much better they'd be in that regard.
Mid-June is still very wintery on the Beartooth Plateau. Snow will be abundant (and not necessarily well consolidated), creeks running high much of the month (but perhaps lots of snow bridges?). Snow storms with significant accumulation are not uncommon. High temps may not crest 40°F, lows could drop below 20°F or lower at high elevations.
More importantly, it is possible that the road to the trailhead will not be passable at that time of year (it tops out at 8800ft). Check with the USFS folks on that one. Even one good sized drift will shut down that road for a while. On the other hand, it is a motortoy playground, so someone might break trail. But you may be approaching from the highway in mid-June.
The Fisher Creek SNOTEL site is a stone's throw from the trailhead and should give you a good idea of snow conditions as well. Currently, 100" of snow on the ground. Last year on April 6th 2011 we had 135" (a better snow year). The last snow melted off on July 18th 2011 (there was still 58" on July 1st 2011) 2011 was unusual though. Most years it looks like the snow is gone around July 1st at that site.
Great info, and it's sounding more like a real possibility if we time it right with the road.
For comparison, i've been 3 times in the Wind River range in June. That's more trailed and less remote for sure, but conditions at 11,500' there in June ought to be similar to conditions at 9,500' in the Beartooths, right?