Carry an ice screw for crevasse rescue
When you're on a glacier climb with a moderate to high risk of a crevasse fall, consider carrying an ice screw.
If you do fall into a crevasse, you can hopefully sink the ice screw and clip yourself to it. This can take your body weight off the rope, which will make life a LOT easier for your partner(s) on top to set up a hauling system, or allow them a bit of slack in the rope so they can put some sort of padding under the rope at the lip of the crevasse. If you have a second ice screw (which maybe your partner on top can lower down to you) you could even aid climb your way out of the crevasse.
The more obvious use is anchor building up top. You'll want a longer screw (16 cm minimum) to be sure you get good purchase in the glacial ice, which is often not the best quality.
For the weight conscious, it's hard to beat the Petzl Laser Speed Light ice screw (photo above). They have steel teeth, an aluminum tube, and are about 40% lighter than a similar steel screw.
Here’s a photo of my better side in my Petzl “Tour” harness, a super lightweight harness designed for ski mountaineering and alpine climbing. Notice on each leg loop, there are two elastic tabs designed for holding an ice screw. Even on a minimalist harness like this, Petzl thought it was worthwhile to have a place to tuck away not one, but two, ice screws. It's not for ice climbing, it's for crevasse rescue.
(And no, that’s not a sexy lightweight aluminum screw as mentioned above, but you get the idea.)
This tip is mentioned in the book "The Mountain Guide Manual", by Marc Chauvin and Rob Coppolillo. It’s an excellent resource for more advanced technique, check it out!
