Sometimes you don’t want the weight or mechanical hassle of ski brakes. More, perhaps you need something that’ll keep a lost ski from rolling into a crevasse. In such cases, “leashes” or “safety straps” are the gear of choice.

Dynafit backcountry skiing binding with custom lightweight safety leash system.
European standards dictate that ski safety straps sold with ski bindings be complex and heavy contraptions that might have their place for making SURE you ski never comes off your foot. Such straps may be appropriate in certain situation, and to their credit they do usually include a slick quick-release system that would be handy if your strap is under tension and you need to get-out-now. But standard leashes are frequently overkill, and they’re so strong you may not completely loose your ski in an avalanche. More, most OEM leashes weigh in the neighborhood of several ounces — way too heavy for an add-on.
Hence, I’ve been using a DIY lightweight leash system for years. Here are the details. (Please note, this system is designed to let go in a high force situation such as an avalanche, so is not recommended for resort use where a runaway ski could be a safety hazard.)

Lanyards with clips, from Office Depot. On the right, 2-pack of item 74458 from Avery is the one we like.
Since I published this system years ago in my Dynafit FAQ, I’ve seen scores of people who’ve cobbled similar rigs using everything from carabiners to knots. Many such systems are too bulky and complicated. Some are too weak, others too strong (such as those using steel cable from telemark bindings.)
Key is using a clip that’s the correct strength. Best we’ve found is one we take off the Office Depot “Avery Neck Hanging Lanyards” 2-pack, item 74458. Or if you want something that will let go easier, but is somewhat weak, you can use the clip from Office Depot “Black Lanyards” 10-pack, item 754-521. The strength of these clips is quite different, so beware and use the stronger if in doubt. More, buy several pair and test the strength yourself. You may find this system seems too wimpy. If so, go to a stronger clip of the variety you can find in hardware stores.

Remove the clip from the lanyard.

Tie a loop of lightweight cord under the boot tongue holder. You can also drill a hole in the toe of the boot and run a knotted cord up through that.

Clip with cord. We girth hitch the cord so it stays in position on clip, a drop of epoxy on the hitch helps too.

You can attach the loop to Dynafit binding with two methods. As shown above, you can just drape the loop over the toe latch. This method is quick, but may come off too easily and can be lost while you're carrying skis.

Best method of attaching loop to binding is shown above, and is same as shown in Dynafit literature. You poke a loop through the hole in the binding toe lever, then pass the cord back through the loop, thus creating a girth hitch through the hole.
Variations: One problem with the rig described above is that working the clip with gloved hands can be tricky. Lanyard clips work better when they’ve got something solid to clip to, so we’ve tried riveting a small D-ring to the toe of the boot, or including a small metal ring on the boot loop. Another option is to use a larger and more easily operated clip, such can sometimes be found at hardware stores and have the advantage or disadvantage of being stronger.
Lastly, again, be aware that the small lanyard clips we show above are not particularly strong. Thus, do not use these at ski resorts or in situations where you absolutely can not loose a ski.
WildSnow.com publisher emeritus and founder Lou (Louis Dawson) has a 50+ years career in climbing, backcountry skiing and ski mountaineering. He was the first person in history to ski down all 54 Colorado 14,000-foot peaks, has authored numerous books about about backcountry skiing, and has skied from the summit of Denali in Alaska, North America’s highest mountain.