Access Issue: Seasonal Closure - 2018 Update Details


Blob Rock is a huge, south-facing rock with many routes, ranging from one-pitch sport to four-pitch trad. Most newer routes are well-protected, but some of the old classics are a bit runout.

Due to its complexity, Block Rock is broken into several subareas. From left to right:

West Buttress - is on the far left side of the rock. It is home to trad routes Divine Wind (11b) and Night Stalker (9), and several short sport routes.

Dike Wall - is the smooth wall left of the Central Chimney. It has sport route Wild Cat (11a), a runout bolted route Bearcat Goes to Hollywood (11d), and the crack climb Wounded Knee (11b).

Central Chimney - is the prominent, slanting chimney that runs up the entire rock. The Radlands of Infinity (13a) and Tempest (10c) are the attractions here.

Main Wall - is the area right of the Central Chimney. There are lots of good climbs here, including October Surprise (10b), On Ballet (8+), Cold Fusion (10c), Bolt Cola (10a), and Where Eagles Dare (10b).

Right Gully - is the gully running up the right side of Blob Rock. It is the home of hard sport routes Jolt Cola (12a) and Vasodilator (13a).

Upper East Face - is above a giant chockstone in the Right Gully. It is home to trad route Conan (11d) and sport route Erki Nool (11d).

Getting There

Park in a small pullout on the right, just past Cob Rock. This is about 6.7 miles up the canyon.

A trail begins from the right side of the pullout. Follow it as it zig-zags up the hill. It will take you to the base of the Main Wall of Blob Rock in about 10 or 15 minutes.

53 Total Climbs

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Classic Climbing Routes at Blob Rock

Mountain Project's determination of the classic, most popular, highest rated climbing routes in this area.
5.9 5c 17 VI 17 HVS 5a
On Ballet
Trad 3 pitches
5.10a 6a 18 VI+ 18 E1 5a
P1 of Astrophysics (aka Bolt Cola)
5.10b 6a+ 19 VII- 19 E2 5b
Where Eagles Dare
Trad 3 pitches
5.10c/d 6b+ 21 VII+ 21 E3 5b
Erickson's Crack
5.10d 6b+ 21 VII+ 21 E3 5b
Wild Cat
5.11b 6c 23 VIII- 23 E3 5c
Divine Wind
Trad 2 pitches
5.11c 6c+ 24 VIII- 24 E4 6a
Orange Crush
5.11+ 7a 24 VIII 24 E4 6a
5.11c/d 7a 24 VIII 25 E4 6a
5.11d 7a 24 VIII 25 E5 6a
Erki Nool (WGA)
5.12a 7a+ 25 VIII+ 25 E5 6a
Jolt Cola
5.12a 7a+ 25 VIII+ 25 E5 6a
Bearcat Goes to Hollywood
Sport 2 pitches
5.12d 7c 28 IX 28 E6 6b
The Radlands of Infinity
Sport 2 pitches
5.13a 7c+ 29 IX+ 29 E6 6c
5.13b/c 8a+ 29 X- 30 E7 6c
Elephant In The Room
Route Name Location Star Rating Difficulty Date
On Ballet Main Wall
5.9 5c 17 VI 17 HVS 5a Trad 3 pitches
P1 of Astrophysics (aka Bol… Main Wall
5.10a 6a 18 VI+ 18 E1 5a Sport
Where Eagles Dare Main Wall
5.10b 6a+ 19 VII- 19 E2 5b Trad 3 pitches
Erickson's Crack Main Wall
5.10c/d 6b+ 21 VII+ 21 E3 5b Trad
Wild Cat Dike Wall
5.10d 6b+ 21 VII+ 21 E3 5b Sport
Divine Wind W Buttress aka Comedy…
5.11b 6c 23 VIII- 23 E3 5c Trad 2 pitches
Orange Crush Right Gully
5.11c 6c+ 24 VIII- 24 E4 6a Sport
Extreme Upper E Face
5.11+ 7a 24 VIII 24 E4 6a Trad
Conan Upper E Face
5.11c/d 7a 24 VIII 25 E4 6a Trad
Erki Nool (WGA) Upper E Face
5.11d 7a 24 VIII 25 E5 6a Sport
Jolt Cola Right Gully
5.12a 7a+ 25 VIII+ 25 E5 6a Sport
Bearcat Goes to Hollywood Dike Wall
5.12a 7a+ 25 VIII+ 25 E5 6a Sport 2 pitches
The Radlands of Infinity Central Chimney Area
5.12d 7c 28 IX 28 E6 6b Sport 2 pitches
Vasodilator Right Gully
5.13a 7c+ 29 IX+ 29 E6 6c Sport
Elephant In The Room Right Gully
5.13b/c 8a+ 29 X- 30 E7 6c Sport
More Classic Climbs in Blob Rock »

Weather Averages

Days w Precip
Prime Climbing Season


For my money, Blob Rock is easily the most loaded cliff in Boulder Canyon. It has great variety: multi-pitch trad, sport, steep faces, slabs (scary and not), even some halfway decent cracks. This crag is fairly complex -- better have a guidebook and as of this writing, contains far more worthy routes than are listed on this site. With predominately southern exposure, it is a good cold weather crag; the rub is that it tends to receive a raptor closure around the beginning of February . On the plus side, this closure tends to be lifted earlier than most. Aug 22, 2002
Stefan Griebel
Boulder, Colorado
Stefan Griebel   Boulder, Colorado
What's the deal with all the raptor nesting closures?! Seems like every year they close a new area, this year it's Blob Rock. Pretty soon it will be all of Boulder Canyon, then all of Eldo, and so on until climbing is not allowed anywhere in Colorado between February 1st and August 1st! Feb 4, 2003
I don't get it: while Blob is closed to a few (mostly environmentally friendly) climbers, we're spending millions of dollars a year paving and maintaining roads in National Parks so that every yahoo with an RV, a generator, and a six pack of macro beer can enjoy the "wilderness." Kind of frustrating, not to mention hypocritical, if you ask me.

Does anyone know what the Access Fund's policy on these closures is? Feb 12, 2003
The Access Fund supports raptor closures and works with agencies to encourage cooperation among climbers. Mar 11, 2003
Raptor closures around here are utterly ridiculous. Cliffs get closed without any sign of birds on a yearly basis.And now it is creeping into other critters as well - there are even closures for bats up in the Flatirons.At Ralston Buttes, the crag is closed year-round for no particular animal - it is "a sensitive study area", whatever that means.

This would be merely irritating if there were ANY scientific evidence that the raptors were negatively impacted by climbers. However, since there is absolutely no evidence to support that position, the vast majority of these raptor closures are just downright stupid.

The Access Fund is a group that I support with my fees, and I think they do a good job.They do a lot of good things and have done a great job of buying up properties and access rights on threatened crags.But with respect to closures, they are extremely weak.Their efforts to "work with" certain land management agencies (Jeffco Open Space, Boulder Open Space, the idiots that run Hueco, etc.) would best be replaced with aggressive litigation.

The Access Fund may support raptor closures, but the only reason they do this is to placate land managers that can't be placated. They should get some balls, start a legal defense fund, and challenge every single one of these closures in court.

Mar 12, 2003
Thanks Richard - totally agree. I was talking about this with a friend and his comment was that we should be happy that more is not closed (implying that there are grounds to close more). What a load.

I would love to start seeing litigation against some of these nazi land managers on power trips. I can just see their self-righteous behavior about the whole thing right now. The government sucks. Mar 15, 2003
Ted Lanzano
Boulder, CO
Ted Lanzano   Boulder, CO
My friend's car got borken into at the Blob Rock parking spot a few weeks ago. I would recommend parking at the Cob Rock lot and walking over for better car securtiy (it's only about 50 feet away).I think the Cob lot offers more visibility and it's more populated, both of which could dissuade thieves. Aug 14, 2003
This is a response to Richard Magill's post stating that there is no evidence of climbing negatively affecting raptors. A few years ago a friend and I did a route in late May at Castle Rock in the Platte. The access to this crag is from Wellington Lake, a fee area. The woman who collected our 3$ told us to stay away from the climb with nesting falcons. We asked if you she tell us the specific route or at least crag the birds were nesting on. She could not, but said the nest would be "obvious". We proceded to our route, which I believe was "The Throne Room", saw no sign of nesting and began climbing.Throughout the first two pitches, falcons loudly screeched from adjacent cliffs. At the end of the stretcher 2nd pitch, I pulled into the belay hole to find a nest containing two unhatched large eggs.I was unhappy about this arrangement, but was unwillingly to abandon the route and make 2 raps from (my own) gear anchors, so I established an anchor with gear above the the hole and my feet resting on the edge of it; this was likely the most common way to rig this belay and the most expeditious, which in view of the threatening weather, was a concern. I brought my partner up, explaining the need for delicacy in the vicinity of the belay.We were not swinging leads, so the belay changeover was protracted; in the hurry to outrace the weather -- we eventually pulled buzzing ropes from the summit rappel and, in shirt sleeves, were pounded by hail on the ensuing raps -- my partner forgot about her out-of-site feet in the hole and stepped on the nest, crushing an egg.

Hard not to call that a negative impact. Sep 27, 2003
Yes, I would agree that actually climbing through the nest and breaking eggs is a negative impact.I would not recommend climbing on a line with a nest on it.

However, I don't see any scientific evidence that climbing a line nearby (say even 10 feet away) has any impact on raptors.

So if there is one nest on a crag, why close the whole crag? Why not just close the line with the nest (and maybe some adjacent ones).Closing all of Blob Rock over one or two nests just doesn't make any sense. Sep 29, 2003
Are 3 and 8 transposed in the topo? I thought the lost Flatiron was between Sherwood and Cob. Sep 29, 2003
In response to climber's impacts on raptor nesting:

While there may not have been an environmental impact assessment done on climbers per se, full with population parameter data, the negative impact of humans on nesting birds is clear. As mentioned by "anonymous coward", the raptors were "screaming" at the climbing duo for the length of the climb. This means that the female was not sitting on the eggs during this time. Incubation is CRITICAL for the developing egg. Raptors are extremely sensitive to humans. Humans anywhere near a nest-- whether it's climbing the line the nest is on, or anywhere near it, will disrupt the mother. Stress during incubation can damage the embryonic development of the chicks; stress on the parents following hatching of the eggs can damage the natural development of the chick, and may lead to an early death. Developing birds are fragile.

Further, remember back to your basic ecology. Raptors are K selected species-- long-lived, slow reproducers. Their populations don't explode like rabbits. Their populations are fragile, and without nesting protection, can crash quickly.

I think the birds might say to you, Stefan, get your own rock. And since they live there and need to reproduce there, and there's plenty more rock in Colorado, maybe you should. Nov 9, 2003
William McGehee
Choctaw, OK
William McGehee   Choctaw, OK
Paul, I believe the topo to be correct. If my memory serves (and the website seems to confirm this), 200 yards west of Cob Rock is Sherwood, then another 100 yards west lies the approach for the Lost Flatiron. I find it easier to walk along the road and use Sherwood's Tyrolean as opposed to Cob Rock's. You avoid scrambling over the boulders at Cob's base.~Wm Nov 9, 2003
Anecdotal stories about the impact of humans on raptors are apparently easy to come by.However, my point remains the same - there is NO SCIENTIFIC EVIDENCE of any negative impact.Point me to a statistically valid study - there aren't any.

And as far as anecdotes go, I've seen bald eagles living just fine on a Broomfield golf course. Peregrines do well living on downtown sky scrapers.

Stefan is right - the raptor closures are silly. Boulder area land managers frequently close cliffs without any active nests.

I like raptors as much as anyone, but the bottom line is that these closures are not based on scientific evidence. Nov 10, 2003
My friend and I encountered an anchor not listed in the Falcon guide to Boulder Canyon at the top of (what the Falcon guide calls) Blacklight. Currently there are no rap rings, just the two hangers, any objections to adding chains so one may rap without [leaving] gear (as we did)? Nov 27, 2005
Leo Paik
Westminster, Colorado
Leo Paik   Westminster, Colorado  
Forest Service Reopens Climbing Areas in Boulder Canyon
Contact: Maribeth Pecotte, (303) 541-2500

Boulder, Colo. (April 2, 2010) – The Forest Service has reopened some climbing areas in Boulder Canyon that were closed to protect golden eagles during their nesting season.

Security Risk and the Blob Rock/Bitty Buttress areas are now open to climbing and other activities. These areas are located along State Highway 119, approximately 1.5 miles east of Boulder Falls.

These closures help protect a long-established golden eagle nesting territory, including valuable alternate nest sites. Although these areas are being reopened, the Forest Service anticipates reinstating the closures in future years, to allow the eagles to choose their nest site without being disturbed.

The Eagle Rock area remains closed to climbing and other activities and is expected to remain closed through July 31. Signs will be posted at key access points into the areas remaining closed. Volunteers and Forest Service personnel will continue to monitor the areas.
For the most current closure information, check signs in the areas, or visit the Boulder Ranger District web site at…. Apr 8, 2010
Leo Paik
Westminster, Colorado
Leo Paik   Westminster, Colorado  
From Bev Baker, USFS wildlife biologist:

U.S. Forest Service to reopen most climbing areas in Boulder Canyon
Contact: Boulder Ranger Station Visitor Information Services,

(303) 541-2500

Boulder, Colo. March 15 – This Mon., March 19, the U.S. Forest Service will reopen Blob Rock, Bitty Buttress and Security Risk climbing areas in Boulder Canyon. The Eagle Rock area remains closed to climbing and other activities and is expected to remain closed through July 31, 2012. Mar 15, 2012