Hey Man!
I'm a huge newbie (FIRST POST!!) and I've only gone draining 3-4x, so I'm not sure what it's like in your area. I wanted to add my two cents I gathered from several years of winter mountaineering and hiking, which while not all oriented specifically at draining, it may be useful to you!
If you're concerned about slipping on ice, I highly recommend purchasing something akin to Yak Trax or MicroSpikes. They're a bit pricey, but come in all sorts of different sizes, and clip over your boots to give you traction on ice!
Some concerns come with these though that you should be aware of-
These can still skid over ice - you can slide an empty boot with Yak Trax or Microspikes across ice like a bowling ball. For them to be effective, you still have to plant your feet to get traction.
Always know how thick ice below you is, whether in a cistern or a lake. If you're not sure its solid enough to hold your weight, don't step on it.
The downside to these, is walking on concrete will absolutely wear them down quickly, when I'm hiking I tend to strap these to the outside of my pack so I can apply them quickly before crossing ice and snow.
Concerning the Yak Trax/Microspikes, your mileage may vary.
I do have some good tips for dealing with cold too! Though since drains are typically warmer than the surface in the cold, this may not be very useful. Again gathered from my winter mountaineering and hiking experience. I could type a million paragraph article about my layering and what I use, but REI has a great base article here:
https://www.rei.co...yering-basics.html One thing to keep in mind is I would definitely not recommend down layers to keep warm, as when down gets wet, its ruined! They recommend all this expensive equipment, which is great, but you can get away with cheaper stuff. One mantra I always have heard in mountaineering is 'cotton kills' when it comes to cold. Cotton is GREAT, but should be saved for summer months. It wicks away sweat really well, which is awesome. The downside here is, especially as a base layer, this moisture cools close to the skin, reducing your body temperature. This can lead to potentially deadly hypothermia. I love and always recommend wool, but there are tons of materials out there that work well too!I do acknowledge, however, that a LOT of this may be overkill in terms of draining. I generally only use a full three layers (base, insulation, shell) on extended (5+hr) adventures at or below freezing.
Regarding your heat pack question - I use these when I hike for my fingers and toes! They can be great! I'd recommend the air activated ones if you decide to use them. Some models (I only have one) use lighter fluid, such as the Hakkin Peacock. This is great because you can always refuel them when they run low, but, they do use oxygen as far as I know. This might make them less than beneficial where you are, but I am too much of a noob to make more than an educated guess here.
Thank you for reading a huge noob's 2 cents! Now, I forgot to introduce myself on the main thread and now that I can post, I'm off to do that!
I can't answer a ton of questions about draining in general, but let me know if you have any other cold weather questions. I do 6-10 winter climbs in Colorado a season at least (less recently because my schooling is picking up pace :/ ), so while I may not be a bear grills level expert, I can definitely give some advice!
Good luck on your adventures!
EDIT: incorrect word usage fixed