Lower Falls includes three main flows approx 160+ feet in length. The climbs are easily visible from the road as you drive up Boulder Canyon just past Castle Rock. These climbs, together with Upper Falls provide the best beginner and after-work ice climbing in the area. The non-existent approach, easy toprope access and mix of difficulty make for an excellent sport-park close to home. As one would imagine, the area is often very crowed on winter weekends. Be courteous to other parties, wear your helmet and belay in a safe location sheltered from falling ice. All the ice here is formed from cracks in the aqueduct above.

A huge debate ensued in the fall of 1997 when a group of climbers increased the number of climbs here by farming ice by siphoning water out of the aqueduct with garden hoses. The most spectacular of these was a 300 foot icefall on Vampire Rock. The authorities finally found out about the climbs and pulled the hoses out and locked grates over the holes. The Boulder Ice ClimberÂ’s Coalition was established to legally farm ice on the routes; however, attempts to negotiate with Public Service Company (who owns some of the water in the aqueduct), the city of Boulder and the National Park Service have failed to produce an agreement.

As these routes are popular, be considerate of the climbing community by not climbing these routes until the ice has had sufficient time and cold weather to form. Thin ice that is not well adhered to the underlying rock is very fragile and destroying the base layers by climbing them prematurely can set back the formation of the climbs several weeks.


Eds. As per Boulder County Parks and Open Space staff, this is on Boulder County Parks and Open Space land! Please follow their regulations. Thanks.

Please carefully check the regulations at the particular ice venues before permanently altering the rock. The canyon consists of a complex gridwork of different landowners. Each landowner may have different regulations. Some have even posted them on site. This is important for maintaining good relations and climber access. Thanks.

Getting There

About 12 miles up the canyon, Castle Rock looms up on the left side at the apex of a right hand turn. Turn off just past the rock to a large dirt pullout directly underneath the west face. Head right across frozen Boulder Creek to reach a well-packed trail, continue 100 yards to the right to the ice. Talk about easy access!

9 Total Climbs

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Location: Castle Rock/Lower Falls Ice Change
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Classic Climbing Routes at Castle Rock/Lower Falls Ice

Mountain Project's determination of the classic, most popular, highest rated climbing routes in this area.
The Bouldering Area
Trad, Ice
WI4 M3
Ouray for Boulder
Trad, Mixed, Ice
Blame James
Trad, Ice
Route Name Location Star Rating Difficulty Date
The Bouldering Area
WI2-3 Trad, Ice
Ouray for Boulder
WI4 M3 Trad, Mixed, Ice
Blame James
WI3+ Trad, Ice
More Classic Climbs in Castle Rock/Lower Falls Ice »

Sun & Shade

Weather Averages

Days w Precip
Prime Climbing Season


Lower area continues to build with melting snow on slopes above and more water coming out of the P.S. pipeline. Low-angle ramp now ready and several lines in to the top. Upper area is melting with the warm and sunny days but re-builds at night and is great in the mornings. I saw a 300-pound block of ice come crashing down yesterday (I was climbing above, thankfully) so be careful where you belay and always wear your helmet, even between laps. Feb 3, 2002
Lower area is building nicely. Far left climb is in to the top although top section is quite wet. Middle climb in solid down low but peters out near the top. Short but fun curtain is good for laps. The Ramp is building and climbable but stepped out and ends short of the top. Walk-off is mostly dry and safe for hiking boots only. Lots of dinner plates and some brittle ice so watch out if anyone is above you and be careful where you belay from. Helmets are a must with all the traffic and debris coming down. Have fun! Feb 6, 2002
Climbed the main flow on 2/7/02. A little wet in spots, but good fun. Led it up, then rapped part way down and set up a top rope. Excellent place to be in the late afternoon - then sun hits the base and makes a nice warm spot to belay from. It was warm enough that we could have climbed rock in the morning and ice in the afternoon or vice versa. Got excellent beta from Neptune Mountaineering also - Thanks! Feb 8, 2002
I bouldered around in the little cave area this morning and did the Middle Flow Route. Wind, warm, and still somewhat decent. The bouldering area has a lot of running water to the right of the little vertical spire. The Middle Flow has excellent plastic placements, still steep, but potholed out a lot for easy placements. It would probably be best to avoid the short semi-vertical section at the top right side of the flow and go left instead, as a layer of running water is under a thin ice crust. If the weather is cold over the next few days, we probably will have the ice around for at least another 1-2 weeks. Enjoy! Apr 1, 2002
Craig Quincy
Louisville, CO
Craig Quincy   Louisville, CO
B.C. is looking pretty bad and another big cold snap will be required for it to rebuild. It has unfortunately melted a lot since a few weeks ago. Dec 1, 2002
George Bell
Boulder, CO
George Bell   Boulder, CO
Conditions up Boulder Canyon past Castle Rock are the leanest I've seen in years. It's pathetic compared to incredible the ice farming years (January 1998 was great). Good if you are practicing your mixed skills, I suppose. Jan 22, 2003
Climbed The Ramp and Main flow this afternoon, in pretty decent as compared with last year, still a lot thinner as compared with pre-2002, I assume since they fixed the leak a few years ago. The right side of Main Flow is now in and looks like the ice in the bouldering cave may touch down to form some of those short pillars of years past. Now go climb here everybody, so Vail might be a little less crowded!! Cheers, AK. Dec 13, 2005