You should really post your audiogram in your signature to begin with, so at least we know what your hearing loss is like to get an idea of why you’re having issues with HAs in noisy environments.
But you did describe it here a little bit: extremely sensitive to the mid range (which I assume to be very normal hearing in low range, and maybe even better then normal hearing mid range), quite insensitive to higher frequency sounds, good enough to get by daily without aids -> sounds like a typical curve loss, but maybe the ski slope is a bit further out at 2 or 4 KHz maybe? And that’s probably why you can get by without aids, because if your ski slope is quite far out, you have normal hearing in the majority range of speech, except maybe you miss out on the s and sh’es, but there’s still plenty of content in the speech for you to catch to make sense of without needing the HAs. Maybe you just can’t hear the birds tweeting or crickets chirping on the high ends.
I’m no audi but I’m just guessing here that in noisy environments, maybe the HA’s amplification of the high frequencies (needed to compensate for your high end loss) is interfering with your being able to hear the mid range somehow, therefore causing your hearing to become ineffective in noisy environments. This is not your HA’s fault because it’s doing its job like it’s supposed to do (amplifying the high ends for you), but maybe you have some kind of special hearing condition/issue where too much high end amplification of the noise mess up your mid range hearing. This may be a rare condition that you have but most other folks don’t have and that’s why the HAs work out OK for them in noisy situation but not for you. And I’m not talking about “ear” hearing here, I’m talking more about “brain” hearing, meaning that maybe your brain is wired a little differently and it just can’t process sounds in the mid range properly if there’s too much high end interference due to noise.
Of course all this is just guessing, who knows for sure. But maybe these special devices from Bose or Nuheara or Doppler Labs will work better for you in noise, just because they’re more generic and focus more on noise cancellation/reduction and beam forming but don’t amplify high ends like your HAs do, so they won’t interfere with your mid range hearing for the speech in noise.
If you find that these devices actually indeed work out better for you in noisy environment after all, maybe one thing to try with your HAs is to lower amplification on the high ends but only when in noisy mode, but retain normal high end amplification in all other modes (like regular or quiet or music modes, etc). I don’t know, just something worth tinkering with if there’s nothing to lose to try it out. The idea here is that your HAs have noise reduction and beam forming features just like those devices, maybe even better. So if those devices work for you in noise and the only difference is that your HAs also amplify the highs, then remove that amplification in noise to make your HAs behave more like those devices.