Even with your ability to signal your position in an emergency, SAR might not have the ability for a quick rescue in temperatures approaching -30C (wind chill @ 50mph will approach temperatures around -60C ). These are very very cold temperatures approaching Antarctic expedition temperatures so you will need a sleeping bag and mat used from the expedition kit lists used in the Antarctic.

Here is a typical Antarctic sleeping bag. Expensive yes but so are missing a few toes and fingers.

http://www.phdesigns.co.uk/product_info.php?products_id=66

An Exped Downmat 9 Deluxe is also an excellent choice for a ground mat

http://www.rei.com/product/780366

A Goretex Bivi bag would also be extremely useful even though the sleeping bag above has Drishell outer fabric. A Vacuum Flask is a must in very low temperatures for keeping water in a liquid state, which is essential in such dry and arid conditions.

BTW there isn't that many calories in Mountain House freeze dried packs. I would just take along lots of chocolate. As you can see from the quantities in the British Antarctic Survey BAS ration pack

http://www.photo.antarctica.ac.uk/external/guest/detail/cart/10003853/1/8

Lots of Cadbury's Milk Chocolate are shown in the BAS ration packs