I received one for Christmas and was wondering if it is supposed to go over jacket or under. I wore it over the other day for my first ski day of the season and the line froze (it was cold, minus 5 when I left).
I wear it over my coat otherwise my coat is too restrictive. My camelback also holds some tools and power bars. I fill it up so I don't have to refill (hate to stop). Also I can move the camelback up (without taking it off) to give me more room on the lift.
Blowing back on the hose is a good solution for freezing hoses and bite valves. The bite valve comes off so you can melt it in your mouth. I have been known to put the camelback on my chest under my coat to defrost it. Mine is a winter specific pack with a rubber cover for the bite valve and insulation. There is also a pocket in the shoulder strap which you can put a chemical warmer in so when you put the hose and valve back in the strap it will stay warm. I don't use that. Blowing back the water does the job 99% of the time.
Perhaps an insulated line could help you out some. I've found the MSR Dromedary bags to be nice at withstanding temperatures. Haven't gotten to try the bag at quite that cold, but so far it seems to be good at withstanding the environmental factors. The above suggestion by MastersRacer of ensuring that you blow the water back in the bag seems to help too. A lot harder to freeze the thick volume of a bag vs. the thinner hose with more exposure. Even sucking just a little water in occasionally (say every lift ride) to keep a flow of water and break up the freezing process should help.
I have a very small REI pack with a camelbak bladder inserted inside. Just right to hold a gaiter, granola bars, cell phone(seldom), and a fleece vest. Took several steps that seem to work for the camelbak bladder. One -- always blow back, as discussed (even with the insulated tube, if I don't below back and colder than 20 get tube freeze-up). Two replace the generic Camelbak tube with a Camelbak insulated tube (takes about 10 minutes, not tough). I wear the pack outside my jacket; fill up the bladder NMT 3/4 full, so when I am on the lift not putting too much pressure on the bladder with the seatback. Found for me, in CO, that if the kids and I go through most of the bladder's contents in 4-6 hours really helps with the altitude/dehydration headaches. Again most important is to always do the blowback routine after drinking.
+1 on the blowback. I also stuff the tube all the way into the pack, with only the mouthpiece exposed. Finally, I fill the bladder with hot water. I'd rather drink hot water when it's cold; keeps my back and the tube warm. I wear the pack on the outside.
Depends on the size of the Camelpack. If it's a small one and will fit, wear it under your jacket and heep the hose inside.
I've used a larger one, but even with insulated tube and blowing back it would freeze up when temps start to get below zero. One additional trick is to drink consistently, every 5-10 minutes...the colder it gets the more often you need to drink to keep the tube/mouthpiece from getting a blockage that won't clear easily.
On super cold days, I either don't ski with it, or I just accept that I'm going to need to go inside a couple of times to warm it up and get the water flowing again.
Just a little more clarification on blowback is to ALSO take the bite valve and squeeze it to get the dribble out (you know what I mean ) otherwise the bite valve can freeze up with the tube is empty.
Yeah, those are nice. My 'winter' Camelbak pack came equipped with one of those and the insulation kit standard. It helps, but in VERY cold weather it will still freeze if you don't get some circulation through the hose or blow back air to keep the hose clear.
They make some low-profile hydration packs that can be worn under a jacket -- but they usually are only 1L capacity (or less) and have little if any storage space. Any kind of 'backpack' is going to work a lot better over your coat.