CSMC Glacier System Canadian Drop Loop

Transcription

1 CSMC Glacier System Canadian Drop Loop Overview This document provides an overview of the Canadian Drop Loop (CDL) system used by the Calgary Scrambling and Mountaineering (CSMC) club and some of its prerequisites. Content is provided with permission by Mountain Skills Academy [ (877) ] and other public sources. Prerequisite Knots Figure 8 required: used to tie into rope, follow through and on a bight Butterfly optional: can be used to tie into middle of rope (figure 8 can also be used) Clove hitch required: used to fix rope while allowing for easy adjustment Munter required: used to belay as per belay device Prusik required: used to move up and down the rope Required Gear Keep in mind that the gear may be distributed amongst a rope team so team minus victim has enough gear. Rope: Distance between members must be greater than size of crevasses. Around the Rockies that means 7-12m. Tie in: Locking carabiner, non-locking carabiner Prusiks: 5m long prusik and 2m short prusik Anchor Slings: 2m sling for anchor (1 additional sling in summer for 2 nd anchor point) Anchors: Skis for winter or ice axe / ice screw(s) / picket for summer (need 2 anchor pieces in the summer) Anchor carabiners: 1 locking for prusik, 2 locking backup, 1 locking for start drop loop Ratchet: Autoblock (or flat faced pulley and short prusik) and 2 locking carabiners Drop loop: Locking carabiner and pulley Anchor ❶ 1. Arrest the fall. 2. For ski T-slot anchor : Rope team members farthest from victim hold the fall while closest surface member is freed to dig T-slot anchor. 3. Probe the area to be dug out to make sure no crevasse is below. 4. Be sure the T-slot will be perfectly perpendicular and centered to the crevasse and victim s rope. 5. Dig T-slot length of skis. For summer use an ice axe. Wide enough for skis to be put into the slot. Be sure to create a chimney in the middle of the T-slot (perpendicular), starting from the very bottom of the slot and rising towards the surface at a low angle. Remember that quality of snow dictates how deep the T-slot should be. In some cases the snow needs to be packed down and let sit a few minutes to firm up. Be sure not to disturb the front retaining wall of the T-slot. 6. Once dug, skis are strapped together and edges padded. A sling is then clove hitched around the skis. Run the sling up the chimney and the end loop is the anchor tie in point. 7. Back-fill the hole. Again do not disturb haul side wall. 8. Now you are ready to transfer the victim s load to a prusik put onto the victim s rope and clipped with a figure 8 on a bight with a locker to the anchor. Rescuers move forward to test anchor. Anchor holds? Yes, then back up victim s main line behind the prusik with clove hitch on a bight to anchor with locker. 9. Now the rescuers are freed from the system and the victim s load is onto the anchor. ❶For summer use 2 of the following: ice axe, ice screw, picket connected with 2 load normalized slings for redundancy CSMC-GlacierSystem-V05.docx Page 1 of 10 Calgary Scrambling and Mountaineering Club.

2 CDL System 1. Closest (2nd) person arrests fall and usually this person builds the anchor assuming enough space to the crevasse. 2. CDL Step 1: Farthest members hold the weight while closest digs T-slot anchor. 3. CDL Step 2: Skis are padded and clove hitched with double length sling. 4. CDL Step 3: Anchor person member transfers the load to the T-slot with a prusik on victim s rope. 5. CDL Step 4: Anchor person backs up the main rope by clipping it behind prusik with a locker and figure eight on a bight to the anchor. 6. Farthest member moves up slightly to test anchor. 7. If anchor is solid, transfer the weight from 2 nd to prusik. Other team members then deploy their prusiks (clipped to harness focal point w/locker), remove fig. 8 tie in point and advance towards anchor while bringing up slack with prusik and probing thus guarding their fall potential into another crevasse while on approach to anchor. 8. Communicate with victim. Is external help required? (SPOT, ELB, Radio ) 9. CDL Step 5: 3rd team member approaches the crevasse lip with prusik while probing. Prepare the lip with shovel and pad the lip- secure lip pad with ski pole, ice axe, etc.. Be sure to secure the items with an ice axe or ski pole(s). 10. Is there an easy option for victim to walk, ski or climb out of the crevasse? Can the team members simply pull on the rope to extract the person from the crevasse? 11. Are you dealing with an un-roped victim? 12. Do you need to rappel into crevasse? Initiate Rescue 1. CDL Step 6: If victim can help, drop a loop with locker from surface to victim and ensure they clip in with carabiner and that it is locked. Keep ropes uncrossed and neat to reduce drag and minimize chance of human error. 2. If rope team is insufficient to pull out the victim using the drop loop only, set up z-pulley for mechanical advantage. 3. CDL Step 7: Put a ratchet onto anchor (Auto block preferred: Reverso or ATC guide or prusik/pulley). Clear snow from beneath ratchet and anchor area for a cleaner system. 4. Put haul side of drop loop into ratchet and test ratchet. 5. CDL Step 8: In front of ratchet, put a hauling prusik onto haul side of drop loop. Tie a haul knot (overhand knot) onto the prusik as close to the prusik barrel as possible. Clip carabiner into this haul knot for hauling. 6. CDL Step 9: Clip haul rope from the haul side into the hauling prusik and slide prusik as close to crevasse lip as safely possible. Begin to haul. 7. CDL Step 10: Reset prusik and continue. 8. Be sure drop loop runs over lip pad. 9. Beware of lip chunks falling on victim when hauling. 10. Communicate with victim to help hauling. 11. * Remember to be clipped into the rope with a prusik at all times as you move forward probing towards the lip. Reverse raise to a lower: 1. If you need to reverse the system go back to default position. Reverse the auto lock with a munter hitch backup. The prusik/pulley alternative can be reversed by taking weight off of prusik and wiggling the prusik. CSMC-GlacierSystem-V05.docx Page 2 of 10 Calgary Scrambling and Mountaineering Club.

3 Main CDL Schematic Crevasse Drop loop with locking carabiner, optional pulley to reduce friction 6 Victim in crevasse Surface 5 Pad crevasse lip & secure lip pad Original strand Prusik with haul knot for hauling 8 Hauling carabiner clipped to prusik 9 3 Load transfer prusik clipped into anchor with locking carabiner Re-direct haul rope from autoblock/prusik (7) and pull here 10 4 Original main rope clipped into anchor with locking carabiner to backup prusik Ratchet (autoblock or prusik) 7 Anchor Skis Rope end tied to anchor 4 2 Sling clove hitched to skis 1 T slot hole (probe to ensure no crevasse below! CSMC-GlacierSystem-V05.docx Page 3 of 10 Calgary Scrambling and Mountaineering Club.

4 Tie In 2 carabiners, 1 locking, 1 regular, opposing gates Prusik on opposite sides for person in middle Figure 8 or butterfly knot Transfer CDL Step 3 Weight slowly released by middle person while rear person backs up anchor Other prusik can be moved to [X] and clipped into with another locking carabiner before unclipping tie in X Prusik adjusted for full length Prusik clipped into anchor locking carabiner CSMC-GlacierSystem-V05.docx Page 4 of 10 Calgary Scrambling and Mountaineering Club.

5 Prusik Fully Weighted Middle is tied into this prusik not shown. If middle is to inspect the lip this prusik needs to be at [X]. Weight now on prusik X Clove hitch knot to backup prusik Backup Main Rope CDL Step 4 As victim ascends keep taking up the slack on this side of rope to backup system CSMC-GlacierSystem-V05.docx Page 5 of 10 Calgary Scrambling and Mountaineering Club.

6 Start Drop Loop Clove hitch from [A] to start drop loop A This strand will go to victim CSMC-GlacierSystem-V05.docx Page 6 of 10 Calgary Scrambling and Mountaineering Club.

7 Drop Loop Simple CDL Step 6 If enough people pulling this is the haul part of rope Pulley to reduce friction with locking carabiner. Pulley optional. CSMC-GlacierSystem-V05.docx Page 7 of 10 Calgary Scrambling and Mountaineering Club.

8 Ratchet Simple CDL Step 7 Locking carabiner Autolock device As victim ascends keep taking up the slack on this side of rope to backup system Original thread holding victim s fall Haul here if enough people Drop loop down to victim Up from victim Locking carabiner Pull here if enough person power Drop loop to victim Drop loop from victim CSMC-GlacierSystem-V05.docx Page 8 of 10 Calgary Scrambling and Mountaineering Club.

9 Pulley Ratchet Alternative CDL Step 7 If an autoblock device is not available a prusik / pulley with flat edge will work as well. As victim ascends keep taking up the slack on this side of rope to backup system Original thread holding victim s fall Haul line Drop loop to victim Drop loop from victim Short prusik Locking carabiner to anchor Pulley with flat edge for prusik to stop against CSMC-GlacierSystem-V05.docx Page 9 of 10 Calgary Scrambling and Mountaineering Club.

10 Mechanical Advantage Z pulley CDL Step 8, 9 If there aren t enough people with sufficient strength to pull out victim with simple drop loop advantage then one more step is required to gain a 6:1 advantage. From autoblock or pulley/prusik Haul line Optional pulley to minimize friction Locking carabiner Drop loop to victim Drop loop from victim Short prusik, as close as possible to crevasse lip ~ End of Document ~ CSMC-GlacierSystem-V05.docx Page 10 of 10 Calgary Scrambling and Mountaineering Club.